This document summarizes a study to reduce noise levels in an automotive testing center's quiet room. Vibration from mechanical equipment on a floor above was transmitting noise through the ceiling into the quiet room, making low-level vehicle tests impossible. An investigation found the quiet room's suspended ceiling was not properly isolated from the floor above. Recommended fixes included improving the ceiling isolation, adding sound absorption, and breaking the floor to isolate vibration transmission. Initial phase 1 work above the ceiling showed promising results in lowering noise levels.
The document discusses the Thermal Bypass Checklist created by ENERGY STAR to address issues they found with homes passing blower door tests but still experiencing energy losses. The 16-item checklist covers areas like air sealing around tubs/showers on exterior walls, insulating floors above garages, sealing attic knee walls and access panels/pull down stairs. Each item is explained with examples of proper and improper installations. Inspecting for bypasses requires removing insulation to check for thorough air sealing. The checklist aims to achieve continuous alignment between the air and thermal barriers throughout the building envelope.
The document discusses under floor air plenum construction for an ASHRAE summer meeting. It provides information on basic plenum design, construction documents, controlling leakage during construction, and real world examples. The key topics covered are plenum materials like raised access flooring and sheetrock, ensuring proper documentation in construction drawings, categorizing and avoiding air leakage, and tips for installation like pre-installation inspections and designing effective air dispersion patterns and ductwork layouts.
This visual dictionary defines and provides images for common construction terms across several categories. Key terms summarized include:
- Air barrier paper, which reduces air leakage and protects from moisture during construction.
- Attic ventilation components like soffit vents, ridge vents, and gable vents which vent heat and moisture from attics.
- A backhoe, which is construction equipment used for excavation through a digging bucket on an arm.
- Brick bonds like running bond and Flemish bond used to construct brick walls.
- Electrical components including transformers, meters, and service panels that distribute electricity.
- Framing elements such as floor joists, studs, and rafters that
The document describes TECEdrainline shower channels, which come in glass, stainless steel, and "plate" tileable options. They are designed to clear bathrooms of obstructions and allow for barrier-free, generous space design. Various installation methods are outlined, including options for close-to-wall installation and use with natural stone floors. Sound insulation products are also highlighted. TECEdrainline channels are available in standard lengths and custom sizes and come in a variety of grate designs.
The document provides information on various building materials and components used in construction. It describes air barriers that prevent air penetration, various types of attic ventilation components like soffit vents, ridge vents and gable vents. It also summarizes tools used in site work like backhoes and bulldozers. Additionally, it outlines different types of cladding, framing elements, electrical components, insulation materials, plumbing fixtures, roofing materials and windows.
The document defines various construction and building terminology through descriptions and pictures. It covers topics such as air barriers, attic ventilation, backhoes, batter boards, brick bonds and sizes, bulldozers, cladding, concrete joints, electrical components, framing elements, front-end loaders, gypsum board, heat pumps, insulation, lintels, oriented strand board, plumbing, plywood, radiant barriers, rebar, roof drainage, roof materials and shapes, stone, vapor retarders, waterproofing, weep holes, and windows.
This visual dictionary defines and provides images of various construction materials, tools, and methods. Key terms include air barriers, attic ventilation types, backhoes, batter boards, brick bonds, concrete joints, concrete masonry units, doors, electrical components, framing elements, gypsum board, heat pumps, insulation types, mortar joints, oriented strand board, plumbing fixtures, plywood, rebar, roofing materials and components, stone types, vapor retarders, waterproofing, weep holes, welded wire fabric, and window types. Diagrams and short descriptions are provided for each term.
This document provides information on various metal roofing projects completed using Insulating Coatings Corporation's products. It describes 23 different projects ranging from 12,000 to 216,000 square feet involving standing seam, rib panel, and other metal roof types. For each project, it lists the client, location, existing conditions, surface preparation performed, and Insulating Coatings products applied which typically included a primer, waterproof membrane, and ceramic finish coat.
The document discusses the Thermal Bypass Checklist created by ENERGY STAR to address issues they found with homes passing blower door tests but still experiencing energy losses. The 16-item checklist covers areas like air sealing around tubs/showers on exterior walls, insulating floors above garages, sealing attic knee walls and access panels/pull down stairs. Each item is explained with examples of proper and improper installations. Inspecting for bypasses requires removing insulation to check for thorough air sealing. The checklist aims to achieve continuous alignment between the air and thermal barriers throughout the building envelope.
The document discusses under floor air plenum construction for an ASHRAE summer meeting. It provides information on basic plenum design, construction documents, controlling leakage during construction, and real world examples. The key topics covered are plenum materials like raised access flooring and sheetrock, ensuring proper documentation in construction drawings, categorizing and avoiding air leakage, and tips for installation like pre-installation inspections and designing effective air dispersion patterns and ductwork layouts.
This visual dictionary defines and provides images for common construction terms across several categories. Key terms summarized include:
- Air barrier paper, which reduces air leakage and protects from moisture during construction.
- Attic ventilation components like soffit vents, ridge vents, and gable vents which vent heat and moisture from attics.
- A backhoe, which is construction equipment used for excavation through a digging bucket on an arm.
- Brick bonds like running bond and Flemish bond used to construct brick walls.
- Electrical components including transformers, meters, and service panels that distribute electricity.
- Framing elements such as floor joists, studs, and rafters that
The document describes TECEdrainline shower channels, which come in glass, stainless steel, and "plate" tileable options. They are designed to clear bathrooms of obstructions and allow for barrier-free, generous space design. Various installation methods are outlined, including options for close-to-wall installation and use with natural stone floors. Sound insulation products are also highlighted. TECEdrainline channels are available in standard lengths and custom sizes and come in a variety of grate designs.
The document provides information on various building materials and components used in construction. It describes air barriers that prevent air penetration, various types of attic ventilation components like soffit vents, ridge vents and gable vents. It also summarizes tools used in site work like backhoes and bulldozers. Additionally, it outlines different types of cladding, framing elements, electrical components, insulation materials, plumbing fixtures, roofing materials and windows.
The document defines various construction and building terminology through descriptions and pictures. It covers topics such as air barriers, attic ventilation, backhoes, batter boards, brick bonds and sizes, bulldozers, cladding, concrete joints, electrical components, framing elements, front-end loaders, gypsum board, heat pumps, insulation, lintels, oriented strand board, plumbing, plywood, radiant barriers, rebar, roof drainage, roof materials and shapes, stone, vapor retarders, waterproofing, weep holes, and windows.
This visual dictionary defines and provides images of various construction materials, tools, and methods. Key terms include air barriers, attic ventilation types, backhoes, batter boards, brick bonds, concrete joints, concrete masonry units, doors, electrical components, framing elements, gypsum board, heat pumps, insulation types, mortar joints, oriented strand board, plumbing fixtures, plywood, rebar, roofing materials and components, stone types, vapor retarders, waterproofing, weep holes, welded wire fabric, and window types. Diagrams and short descriptions are provided for each term.
This document provides information on various metal roofing projects completed using Insulating Coatings Corporation's products. It describes 23 different projects ranging from 12,000 to 216,000 square feet involving standing seam, rib panel, and other metal roof types. For each project, it lists the client, location, existing conditions, surface preparation performed, and Insulating Coatings products applied which typically included a primer, waterproof membrane, and ceramic finish coat.
This document contains construction details and specifications for a multi-story building including a market place and offices. It includes details on the exterior wall, ground floor, upper floor, balcony floor, glazing system, and roof constructions. All materials and dimensions are specified according to relevant National Building Specification standards. Elevations, sections and plans are provided at a scale of 1:20.
Presentation Design Drawing for Architectural DrawingShane Madden
The document provides details for a proposed town hall building in Hannover, Germany. It will be three stories tall and constructed of a timber frame and brick exterior. The interior will use glu-lam beams and columns with exposed structure. It will have a flat roof and three interior courtyards. Additional details are given for floor heights, wall assemblies, structural connections, and conceptual design.
The document contains plans and details for a timber roof structure designed by Aaron Kaira. It includes a roof structure plan showing timber rafters and purlins, and sections detailing connections. Rafters are 250x50mm timber at 1200mm centers. Purlins are 75x50mm timber at 1200mm centers. Prefabricated box beams are used to support the rafters. The roof is covered with 0.5mm galvanized steel sheeting over rigid board insulation.
This document contains architectural plans for a proposed two-storey home extension including a ground floor addition of 34.66 square meters and first floor addition of 22.08 square meters. The plans show the layout of the existing house and proposed additions, including new windows, doors, rooflights, and structural elements. Construction details are provided for the foundations, walls, floors, roof, insulation, and materials. The project will update an existing house with a modernized layout and improved energy efficiency.
This document provides information on air barrier design and testing for large buildings. It discusses how air barriers can reduce energy costs and improve occupant comfort by limiting air infiltration and exfiltration. Different air barrier designs are described for exterior envelopes and interior partitions. The document emphasizes that a properly designed, installed, and tested air barrier is essential but complex, requiring coordination between trades and quality assurance measures to ensure continuity and effectiveness of the air barrier. It recommends hiring experienced air barrier consultants to help with design, testing, and troubleshooting of large building air barriers.
Angeline Kon_Kee Hooi_0302068_BTech1-P1-Alternative Construction Solution and...Angeline KH
This project involves redesigning portions of an existing nature appreciation centre building utilizing alternative construction systems. The student is required to propose modifications to the floor, wall, roof, and basement systems and document the changes in a report and set of working drawings. Specifically, the student proposes using a composite concrete bondek floor system, glazed timber curtain wall system, steel truss roof structure with profiled metal roofing, and a newly added basement level with micropile foundation. Documentation of the redesign includes modified floor plans, elevations, sections and construction detail drawings.
This home inspection report summarizes the condition of a single family home in American Fork, Utah. Key points include:
- Cracks were found in the foundation walls and basement floor which do not currently require repair.
- The deck needs repair or replacement of wood materials. Caulking is also needed around windows, doors, and in bathrooms.
- The upstairs smoke detector is non-working and needs repair. The furnace was not tested since the gas was shut off.
- Minor repairs are recommended for siding, windows, roofing materials, and insulation on the air conditioner line.
- Overall the home is in satisfactory condition with some improvements needed to address safety, moisture
Platinflex manufactures parallel corrugated flexible metal hoses and metal hose assemblies. They produce gas hoses, water and solar hoses, sprinkler hoses, and anti-vibration hoses. Their gas hoses include EN14800 gas hoses for natural gas connection, EN15266 domestic gas connection hoses, extensible gas hoses, non-extensible gas hoses, gas hoses for gas counters, gas hoses for burner connections, gas hoses for regulator connections, and dilatation hoses for gas connection points.
This document provides details for proposed upgrades to the walls, floors, windows, and structures of a protected mill building and silo. It includes specifications for insulating existing masonry walls, upgrading wood floors, installing triple glazed windows, and adding rigid insulation and cladding to silo walls. Diagrams show wall section details, proposed plans, and structural connection details. The work is designed according to conservation best practices to ensure reversibility of the upgrades.
- The document defines and describes various building materials and construction elements, including air barrier paper, attic ventilation components, excavation equipment like backhoes, framing elements, brick bonds, concrete joints, doors and windows, electrical system components, framing elements, insulation types, masonry units, plumbing fixtures, roofing materials, siding types, steep roof shapes and terms, stone patterns, vapor retarders, waterproofing, welded wire fabric, and more.
- Definitions, typical uses, measurements, and other specifications are provided for each term to concisely explain what it is and its function in construction.
- A wide range of building science
The document is a site plan and specifications for renovations and additions to a property. It includes demolishing some walls, adding new windows and doors, renovating bathrooms, constructing a new garage and boundary walls, and other interior renovations. Dimensions and materials are provided for the new construction. The total existing building area is 227.53 sqm and the new construction will increase this by 72.94 sqm, bringing the total coverage to 31.21% of the 1,197 sqm erf. Health and safety, contractor, and other legal notes are included at the bottom.
This document provides definitions and descriptions of various construction materials and building components. It includes explanations of air barriers, attic ventilation components like soffit vents and ridge vents, excavation equipment like backhoes and front end loaders, foundation components like batter boards, types of brick bonds and brick sizes, concrete joints, concrete masonry units, doors and windows, electrical system parts, framing elements, insulation materials, masonry units, plumbing fixtures, roofing materials and components, siding materials, steel components, and more.
The document provides construction details for a multi-story office and retail building including:
1) Details for the roof structure showing connections between steel beams and columns as well as eaves and drainage details.
2) A detail showing the connection between curtain walling and rainscreen cladding on the 8th floor.
3) Details for the ground floor including load bearing wall connections to curtain walling and fire door head, sill, and jamb details.
4) A detail showing the connection between the building's cavity drainage system and adjacent pavement.
5) A detail of the cavity drainage system for the lower basement level.
This document is a thesis submitted by George van Hout to the University of Canterbury in fulfillment of the requirements for a Masters of Engineering degree. It investigates the acoustic performance of suspended ceiling systems, including measurements of sound absorption coefficients using a reverberation room and transmission loss through the plenum sound path using a newly commissioned ceiling flanking noise facility. The thesis includes background research on porous absorbers and sound transmission, description of the measurement facilities and standards, presentation of results, and conclusions regarding the effect of ceiling tile properties and additional plenum absorption on transmission loss.
This document contains drawings and details for a proposed performing arts centre project. It includes floor plans showing the layout of the ground floor and first floor, elevations of the building, section details, and technical details of the building systems like the floating floor structure, wall assemblies, and roof details. Renderings and dimensions are provided for reference.
The document provides descriptions and definitions of various construction materials, methods, and equipment. It includes explanations of different types of windows, roofs, walls, foundations, insulation methods, and other building components. Photos accompany the text to illustrate concepts like brick laying patterns, window types, roof features, and more. Definitions are provided for technical terms to concisely explain building science topics.
This document summarizes the design, fabrication, and testing of a rotating acoustic diffusor implemented in the NASA LaRC Structural Acoustic Loads and Transmission (SALT) facility reverberation room. A 10' x 6' planar diffusor panel was built from a steel frame covered with corrugated PVC to reduce measurement variance by modulating room modes during data acquisition. Tests were conducted with and without the diffusor rotating, showing reduced variance in noise reduction spectra. Additionally, finite element modeling was used to simulate the diffusor's ability to modulate room modes at different angles. The results indicate the rotating diffusor improves data quality and further investigation is warranted.
This document provides a summary of sound measurements taken in the upper ground floor of an office extension building. Sound levels were too high, ranging from 60-78dB where 35-50dB is recommended. Potential causes of excessive noise were identified as the high inclined ceiling, lightweight plasterboard ceiling material, and insufficient acoustic materials. Calculations of room volume, absorption coefficients, and Sabine's formula were used to determine the current reverberation times were 6.02s at 500Hz and 4.56s at 1000Hz, above the recommended 0.5-1.2s for open plan offices. Solutions to reduce reverberation times and noise levels are needed.
The document discusses methods for controlling noise in buildings. It covers topics like noise and health impacts, sound absorption and insulation techniques, room acoustics design, and controlling noise from HVAC systems and elevators. Methods to improve wall and floor constructions are presented, along with best practices for residential sound control and common mistakes to avoid. The goal is to introduce noise control strategies to create less noisy residential and commercial buildings.
This paper describes the structural design of the Carterton Events Centre in New Zealand, focusing on its seismic resistant system consisting of dissipative timber rocking post-tensioning walls. The auditorium features 11 of these 180mm thick LVL walls, each 6.7m tall and 2.4m long, with a central slot for post-tensioned bars. Energy dissipation is provided by embedded mild steel rods. Non-linear dynamic analysis confirmed the design, showing the walls concentrate damage at interfaces while self-centering to their original positions after seismic events.
Construction of the Boom Room Recording StudioSiddhant FNU
The document provides details on the design and construction of an audio recording studio. It outlines 21 sections to be covered including layout, floating floor construction using wooden joists and drywall, hanging ceiling, custom windows, acoustic treatment, equipment, and software. Key aspects of construction addressed are using a sound lock between rooms, symmetrical design of control room, taller walls in recording room for reverb, and multi-layer wall construction with insulation to achieve an STC of 59. Electrical and HVAC systems are integrated within the walls and roof.
This document contains construction details and specifications for a multi-story building including a market place and offices. It includes details on the exterior wall, ground floor, upper floor, balcony floor, glazing system, and roof constructions. All materials and dimensions are specified according to relevant National Building Specification standards. Elevations, sections and plans are provided at a scale of 1:20.
Presentation Design Drawing for Architectural DrawingShane Madden
The document provides details for a proposed town hall building in Hannover, Germany. It will be three stories tall and constructed of a timber frame and brick exterior. The interior will use glu-lam beams and columns with exposed structure. It will have a flat roof and three interior courtyards. Additional details are given for floor heights, wall assemblies, structural connections, and conceptual design.
The document contains plans and details for a timber roof structure designed by Aaron Kaira. It includes a roof structure plan showing timber rafters and purlins, and sections detailing connections. Rafters are 250x50mm timber at 1200mm centers. Purlins are 75x50mm timber at 1200mm centers. Prefabricated box beams are used to support the rafters. The roof is covered with 0.5mm galvanized steel sheeting over rigid board insulation.
This document contains architectural plans for a proposed two-storey home extension including a ground floor addition of 34.66 square meters and first floor addition of 22.08 square meters. The plans show the layout of the existing house and proposed additions, including new windows, doors, rooflights, and structural elements. Construction details are provided for the foundations, walls, floors, roof, insulation, and materials. The project will update an existing house with a modernized layout and improved energy efficiency.
This document provides information on air barrier design and testing for large buildings. It discusses how air barriers can reduce energy costs and improve occupant comfort by limiting air infiltration and exfiltration. Different air barrier designs are described for exterior envelopes and interior partitions. The document emphasizes that a properly designed, installed, and tested air barrier is essential but complex, requiring coordination between trades and quality assurance measures to ensure continuity and effectiveness of the air barrier. It recommends hiring experienced air barrier consultants to help with design, testing, and troubleshooting of large building air barriers.
Angeline Kon_Kee Hooi_0302068_BTech1-P1-Alternative Construction Solution and...Angeline KH
This project involves redesigning portions of an existing nature appreciation centre building utilizing alternative construction systems. The student is required to propose modifications to the floor, wall, roof, and basement systems and document the changes in a report and set of working drawings. Specifically, the student proposes using a composite concrete bondek floor system, glazed timber curtain wall system, steel truss roof structure with profiled metal roofing, and a newly added basement level with micropile foundation. Documentation of the redesign includes modified floor plans, elevations, sections and construction detail drawings.
This home inspection report summarizes the condition of a single family home in American Fork, Utah. Key points include:
- Cracks were found in the foundation walls and basement floor which do not currently require repair.
- The deck needs repair or replacement of wood materials. Caulking is also needed around windows, doors, and in bathrooms.
- The upstairs smoke detector is non-working and needs repair. The furnace was not tested since the gas was shut off.
- Minor repairs are recommended for siding, windows, roofing materials, and insulation on the air conditioner line.
- Overall the home is in satisfactory condition with some improvements needed to address safety, moisture
Platinflex manufactures parallel corrugated flexible metal hoses and metal hose assemblies. They produce gas hoses, water and solar hoses, sprinkler hoses, and anti-vibration hoses. Their gas hoses include EN14800 gas hoses for natural gas connection, EN15266 domestic gas connection hoses, extensible gas hoses, non-extensible gas hoses, gas hoses for gas counters, gas hoses for burner connections, gas hoses for regulator connections, and dilatation hoses for gas connection points.
This document provides details for proposed upgrades to the walls, floors, windows, and structures of a protected mill building and silo. It includes specifications for insulating existing masonry walls, upgrading wood floors, installing triple glazed windows, and adding rigid insulation and cladding to silo walls. Diagrams show wall section details, proposed plans, and structural connection details. The work is designed according to conservation best practices to ensure reversibility of the upgrades.
- The document defines and describes various building materials and construction elements, including air barrier paper, attic ventilation components, excavation equipment like backhoes, framing elements, brick bonds, concrete joints, doors and windows, electrical system components, framing elements, insulation types, masonry units, plumbing fixtures, roofing materials, siding types, steep roof shapes and terms, stone patterns, vapor retarders, waterproofing, welded wire fabric, and more.
- Definitions, typical uses, measurements, and other specifications are provided for each term to concisely explain what it is and its function in construction.
- A wide range of building science
The document is a site plan and specifications for renovations and additions to a property. It includes demolishing some walls, adding new windows and doors, renovating bathrooms, constructing a new garage and boundary walls, and other interior renovations. Dimensions and materials are provided for the new construction. The total existing building area is 227.53 sqm and the new construction will increase this by 72.94 sqm, bringing the total coverage to 31.21% of the 1,197 sqm erf. Health and safety, contractor, and other legal notes are included at the bottom.
This document provides definitions and descriptions of various construction materials and building components. It includes explanations of air barriers, attic ventilation components like soffit vents and ridge vents, excavation equipment like backhoes and front end loaders, foundation components like batter boards, types of brick bonds and brick sizes, concrete joints, concrete masonry units, doors and windows, electrical system parts, framing elements, insulation materials, masonry units, plumbing fixtures, roofing materials and components, siding materials, steel components, and more.
The document provides construction details for a multi-story office and retail building including:
1) Details for the roof structure showing connections between steel beams and columns as well as eaves and drainage details.
2) A detail showing the connection between curtain walling and rainscreen cladding on the 8th floor.
3) Details for the ground floor including load bearing wall connections to curtain walling and fire door head, sill, and jamb details.
4) A detail showing the connection between the building's cavity drainage system and adjacent pavement.
5) A detail of the cavity drainage system for the lower basement level.
This document is a thesis submitted by George van Hout to the University of Canterbury in fulfillment of the requirements for a Masters of Engineering degree. It investigates the acoustic performance of suspended ceiling systems, including measurements of sound absorption coefficients using a reverberation room and transmission loss through the plenum sound path using a newly commissioned ceiling flanking noise facility. The thesis includes background research on porous absorbers and sound transmission, description of the measurement facilities and standards, presentation of results, and conclusions regarding the effect of ceiling tile properties and additional plenum absorption on transmission loss.
This document contains drawings and details for a proposed performing arts centre project. It includes floor plans showing the layout of the ground floor and first floor, elevations of the building, section details, and technical details of the building systems like the floating floor structure, wall assemblies, and roof details. Renderings and dimensions are provided for reference.
The document provides descriptions and definitions of various construction materials, methods, and equipment. It includes explanations of different types of windows, roofs, walls, foundations, insulation methods, and other building components. Photos accompany the text to illustrate concepts like brick laying patterns, window types, roof features, and more. Definitions are provided for technical terms to concisely explain building science topics.
This document summarizes the design, fabrication, and testing of a rotating acoustic diffusor implemented in the NASA LaRC Structural Acoustic Loads and Transmission (SALT) facility reverberation room. A 10' x 6' planar diffusor panel was built from a steel frame covered with corrugated PVC to reduce measurement variance by modulating room modes during data acquisition. Tests were conducted with and without the diffusor rotating, showing reduced variance in noise reduction spectra. Additionally, finite element modeling was used to simulate the diffusor's ability to modulate room modes at different angles. The results indicate the rotating diffusor improves data quality and further investigation is warranted.
This document provides a summary of sound measurements taken in the upper ground floor of an office extension building. Sound levels were too high, ranging from 60-78dB where 35-50dB is recommended. Potential causes of excessive noise were identified as the high inclined ceiling, lightweight plasterboard ceiling material, and insufficient acoustic materials. Calculations of room volume, absorption coefficients, and Sabine's formula were used to determine the current reverberation times were 6.02s at 500Hz and 4.56s at 1000Hz, above the recommended 0.5-1.2s for open plan offices. Solutions to reduce reverberation times and noise levels are needed.
The document discusses methods for controlling noise in buildings. It covers topics like noise and health impacts, sound absorption and insulation techniques, room acoustics design, and controlling noise from HVAC systems and elevators. Methods to improve wall and floor constructions are presented, along with best practices for residential sound control and common mistakes to avoid. The goal is to introduce noise control strategies to create less noisy residential and commercial buildings.
This paper describes the structural design of the Carterton Events Centre in New Zealand, focusing on its seismic resistant system consisting of dissipative timber rocking post-tensioning walls. The auditorium features 11 of these 180mm thick LVL walls, each 6.7m tall and 2.4m long, with a central slot for post-tensioned bars. Energy dissipation is provided by embedded mild steel rods. Non-linear dynamic analysis confirmed the design, showing the walls concentrate damage at interfaces while self-centering to their original positions after seismic events.
Construction of the Boom Room Recording StudioSiddhant FNU
The document provides details on the design and construction of an audio recording studio. It outlines 21 sections to be covered including layout, floating floor construction using wooden joists and drywall, hanging ceiling, custom windows, acoustic treatment, equipment, and software. Key aspects of construction addressed are using a sound lock between rooms, symmetrical design of control room, taller walls in recording room for reverb, and multi-layer wall construction with insulation to achieve an STC of 59. Electrical and HVAC systems are integrated within the walls and roof.
The document provides details about the Allianz Arena stadium in Munich, Germany. It summarizes the key aspects of the stadium's design including its unique ETFE cushion facade that can change colors to represent the home team. The structural system uses a steel lattice roof structure supported by concrete columns to distribute loads from the air-inflated ETFE surface structure to the foundation. The document also describes the model making process used to demonstrate the structural concepts.
Humidity intrusion effects on the properties of sound acoustic of autoclaved ...eSAT Journals
Abstract Autoclaved Aerated Concrete (AAC) has been commonly known to exhibit favorable thermal properties, high fire resistance and high compressive resistance at relatively low density. However, little attention has been devoted to the sound insulation performance of AAC. One of the points needs to know is humidity intrusion effects on AAC members in areas with high relative humidity levels of Mediterranean climates which are important in durability and insulation properties of AAC. Tests on mechanical and physical properties of ACC carried out to study humidity intrusion effects on AAC members were studied with and w/o coatings on the surfaces. From the findings of this study, physical and mechanical autoclaved aerated concrete evaluated in three different humidity levels to compare the effect of humidity on properties of AAC. According to test results coating is the most important factor for improving resistivity of AAC walls, and these factors help AAC walls to keep their mechanical and physical properties against humidity. With its closed air pockets, AAC can provide very good sound insulation. This paper presents the results of studies on acoustic properties of AAC partitions aimed at identifying the effect of specific factors on AAC sound insulation performance. Keywords: AAC, concrete, humidity, sound acoustic, decibel
This document discusses noise control in buildings. It defines noise and sound intensity, and explains that the goal of building design is to control unwanted noise while enhancing desired sound. It describes common internal and external noise sources in buildings. It also discusses the Sound Transmission Class rating used to measure noise insulation of building materials. Finally, it provides details on construction techniques for walls, windows, doors, floors and roofs to improve a building's acoustic performance, such as increasing wall thickness, using staggered studs, sealing cracks and adding sound absorbing materials.
This document provides information about acoustic panel false ceilings. It discusses the components of a false ceiling including acoustic panels made from glass fiber and a bio-based binder. The panels have a Class A fire rating and are installed by snapping metal channels together in a grid and dropping the lightweight acoustic panels into the grid. Benefits of acoustic ceilings include sound absorption, hiding pipes and wires, and increased light reflection. A market survey for different acoustic panel companies and their product specifications is also included.
Testing methods for better acoustic performanceManan Sethi
Good acoustic is important for building comfortable indoor environment, learn all about testing methods for better acoustic in building façade design
https://wfmmedia.com/testing-methods-for-better-acoustic-building-facade/
Sound Control becomes more important every day.Terry Cotton
SF Products provide sound control solutions for floor/ceiling assemblies using a proprietary composite technology. Their SF 300 product features a lightweight, monolithic layer that provides superior sound performance with IIC ratings up to 70 and STC up to 67, exceeding code requirements by over 40%. It allows for direct attachment of floor goods and is suitable for use in UL fire rated assemblies.
2500 word essay on construction technology Jacob Wotton
The document is an electronic submission coversheet for a student assignment. It includes information such as the student's name and number, course details, word count, and a statement indicating this is the student's final submission. The coversheet must be completed by both the student and staff/tutor. For the student, it involves certifying the work is their own and complies with ethics standards. For staff, it involves providing feedback on the submission.
This document provides information about a structural study of the John Hancock Center in Chicago from 2018-2075. It discusses the building's design concept, which was to create the first mixed-use high-rise with a tapered shape to minimize steel usage and wind loads. A key innovation was the building's use of a trussed tube structural system with exterior diagonal bracing between columns, which allowed for large clear spaces. This system proved efficient at redistributing both lateral and gravity loads throughout the structure.
This document discusses strategies for improving acoustic comfort in air conditioning and mechanical ventilation (ACMV) systems. It begins by outlining some of the key acoustic issues that can arise from ACMV systems, such as equipment noise and vibration, duct noise, and terminal device noise. It then presents three case studies of successful noise reduction projects involving ACMV systems. Measurement techniques and criteria for assessing noise and vibration are also described. The overall aim is to provide guidance on designing and retrofitting ACMV systems to minimize noise and maximize acoustic comfort in buildings.
This document discusses different types of false ceilings, including their purposes, advantages, materials, and installation methods. It describes common suspended ceiling systems like exposed and concealed grid ceilings. Key materials mentioned include gypsum boards, metal panels, fiberboard, and mineral tiles. Installation photos show the process for concealed grid and exposed strip ceilings.
2. Figure 1. Photograph of the Quiet Room showing the extent of sound
absorption surface finishes.
Figure 2. Close-up of the scrim-and-hardware-cloth-faced glass fiber
absorption panels that line the walls and ceiling of the Quiet Room.
Initially, consideration was given to try and directly vibration-isolate
the greatest contributors to excessive Quiet Room noise: the
temperature chamber refrigeration compressors and the main building
electrical switchgear. However, this idea was dismissed due to the
difficulty in addressing an extensive array of pipes and service lines
that connect to the compressors and the large feeder lines and
conduits that connect to the switchgear.
A detailed examination was also made of the original building
design drawings showing the building construction including the
Quiet Room. This review showed that the top side of the Quiet
Room ceiling was formed by galvanized sheet steel panels spot
welded to an angle iron grid that was suspended from the structural
steel and underside of the mezzanine floor deck above using tie
wires. These ceiling panels provided a potential sound barrier
beneath the floor deck with the potential to perform as a double wall
assembly with the floor deck to reduce sound transmission of MER
noise radiating through the deck. We had concerns, however, that
structure-borne vibration in both the floor deck and deck-supporting
structural steel beams would transmit through the ceiling suspension
wires and limit the effectiveness of the ceiling barrier. An added
concern was that the structure-borne vibration also radiates as noise
directly into the above-ceiling cavity, through the ceiling barrier, and
ultimately, into the Quiet Room.
A detailed inspection of the actual building construction was made in
the return air cavity above the Quiet Room ceiling. During the
inspection, we noted that the angle iron and steel ceiling panels were
suspended using steel spring and neoprene vibration isolators,
presumably to interrupt the conduction of structure-borne noise from
the floor deck and structural steel into the ceiling panels. These
isolators were not shown on the design drawings and were apparently
added during construction, presumably to interrupt the conduction of
structure-borne noise from both the floor deck and structural steel
into the ceiling panels. See Figure 3.
Figure 3. Photograph of the space above the ceiling of the Quiet Room
showing the top side of metal ceiling panels that form the ceiling, the angle
iron structural grid that supports these panels, and three of the spring and
neoprene hangers that support the grid from the floor deck above. Also shown
is the existing supply air distribution ductwork and the angled structural steel
that supports a monorail beam in the Quiet Room below.
However, a closer inspection revealed that the spring hangers
employed for this were the pre-compressed type. Pre-compressed
spring hangers are available from hanger manufacturers specifically
to limit movement in the isolated element (e.g., ceiling) as weight is
successively added during construction. In the case of an isolated
barrier ceiling, pre-compressed hangers maintain a constant elevation
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3. of the ceiling as insulation and various layers of the ceiling are
installed, rather than allowing a gradual and continual drop in ceiling
elevation that would otherwise occur. Once the ceiling loading
exceeds the pre-compression setting, the elements that create the
pre-compression become disengaged and no longer are in contact. At
that point, the ceiling load “breaks free” and the springs deflect
slightly further to their final position.
Additional review of the isolating spring hangers that had been
selected and installed to support this Quiet Room ceiling showed that
these hanger springs were pre-compressed by the manufacturer to an
equivalent load of 60 kg (133 lb) per hanger [3]. This was 60% of the
maximum load rating of 101 kg (222 lb) per hanger. The combination
of choosing hangers with load capacities that are too high for this
ceiling under typical isolator spacing, and the use of an excessive
number and concentration of hangers to support this ceiling resulted
in an estimated average loading of less than 32 kg (70 lb) per isolator.
It should be noted here that the installed spacing of the isolators was
not in a simple rectangular pattern, but was instead somewhat
irregular. This approach was chosen by the installation contractor in
part to work around ductwork serving the Quiet Room (see Appendix
for an illustration). The net result was that after construction, most
spring isolators remained in a pre-compressed state such that the
effectiveness of the springs for isolating vibration was compromised
(short-circuited) by the nuts and washers installed to create the
pre-compression. See Figure 4 for a view of one of the compromised
hangers caused by the pre-compression nut and washer.
Figure 4. Photograph of the above-ceiling space with a close-up of the bottom of
one of the isolation hangers. The red arrow indicates the pre-compression nut
that forces the washer against the bottom of the housing causing a “short-
circuit” of the spring and allows vibration to travel down to the ceiling panels.
In addition, inspection of the above-ceiling cavity revealed that there
are three sets of steel framing elements that connect to the underside
of floor-supporting steel, angle downward to penetrate the barrier
ceiling plate, and support a horizontal beam to which a monorail beam
along the top and center of the Quiet Room is bolted. See Figure 5.
These steel framing elements provide a direct path for structure-borne
vibration from the underside of the MER floor deck to the monorail
beam. A photo of one set of this framing (viewed from the above-
ceiling cavity above the Quiet Room) is provided in Figure 6.
Figure 5. Photograph of the monorail beam for a hoist that traverses the
centerline of the Quiet Room in a ceiling recess.
Figure 6. Photo of angled steel framing members that extend down from the
floor deck to support the end of one of three horizontal beams that support the
Quiet Room monorail beam that runs in a ceiling recess along the center of the
Quiet Room. These steel members were also found to conduct vibration into
the metal ceiling panels.
Acoustical Measurements
Measurements were made of the background noise level in the Quiet
Room under various operating conditions of MER equipment. Refer
to Figure 7. Measurements were made in octave bands and compared
against the target noise limit of noise criterion (NC) 15 dB [4]. These
measurement results show that operation of the MER refrigeration
compressors is the most significant contributor to excessive Quiet
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4. Figure 7. Third-octave band noise levels measured in the Quiet Room for
various MER equipment operating conditions compared against the (octave
band) target goal of NC-15.
Room noise. Noise produced by the electrical switchgear was also
found to be a significant contributor to noise in the Quiet Room.
One-third octave band sound pressure level (1/3 OB SPL)
measurements were also made at key locations under specific MER
equipment operating conditions to better understand the noise
intrusion into the Quiet Room. Figure 8 shows the 1/3 OB SPL
measured in the MER at positions ranging from close to and distant
from the refrigeration compressors with the compressors in operation
as well as the switchgear energized. Also shown is the spectrum of
noise measured in the ceiling cavity above the Quiet Room and in the
center of the Quiet Room. These results show that pronounced
spectral peaks in the third-octave bands of 63, 125, 250, and 500 Hz
exist in the MER, within the ceiling cavity, and in the Quiet Room.
Measurements were made of the airborne sound transmission loss
(STL) performance of the floor-ceiling construction separating the
Quiet Room from the mechanical equipment room above using the
test procedure of ASTM E 336 [5]. Measurements were also made
of the noise reduction (NR) versus third-octave band frequency
between the MER and the above-ceiling cavity above the Quiet
Room to approximate the STL of the floor deck alone. These are
plotted in Figure 9 compared against laboratory measured STL data
for the two respective floor and floor-ceiling constructions. It should
be noted that because the actual laboratory STL performance for the
overall floor-ceiling assembly was not readily available, the
performance was estimated using empirical calculations based upon
a combination of the STL of elements that were individually
laboratory tested for STL performance (i.e., 6″ concrete and 18 ga.
sheet steel) [6]. Based upon this comparison, it is clear that the
concrete floor deck performance is reasonably close to that expected
based upon laboratory test data. However, the floor slab in
conjunction with the suspended 18 ga. steel barrier produces
considerably less than its potential as demonstrated by comparison
against laboratory test data. This is attributed to the lack of resilient
suspension of the barrier steel panel ceiling, which is the direct
result of the compromised vibration isolation performance of the
pre-compressed spring hangers.
Figure 8. Third-octave band noise levels measured in the Quiet Room before
corrective measures, as well as above the Quiet Room ceiling, and at several
positions in the MER for various MER equipment operating conditions
compared against the (octave band) target goal of NC-15.
It should also be noted that the apparent drop in STL performance at
125 Hz is actually due to background noise in the measurements
originating from the MER switchgear which could not be turned off
for this investigation (see field test results provided in Figure 9).
Recommended Corrective Measures
Corrective measures for reducing noise intrusion into the Quiet Room
were identified to correct design and construction deficiencies
discovered during this investigation. These included reworking the
suspension system which supports the barrier ceiling plate above the
Quiet Room, and related actions which reduce the airborne and
structure-borne noise transmission into that ceiling barrier. In
addition, a method for interrupting structure-borne noise through the
MER floor deck was also identified. This consisted of first saw-
cutting the floor deck to create a physical break in the otherwise
continuous slab, and second, to interrupt the structure-borne path
through structural steel beams that support that floor deck. The latter
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5. would be achieved by breaking the contact between the ends of those
beams and the main beams along column lines that support the beam
ends. The “freed” ends of these floor-supporting beams would then be
supported using spring isolators. These corrective measures were set
up to be implemented in three separate phases. This approach allows
for measurements of Quiet Room noise levels upon completion of
each phase to determine the effectiveness of the work conducted in a
given phase before proceeding with the next phase.
Figure 9. This graph shows a comparison of the third-octave band sound
transmission loss performance of a 6″ concrete floor slab with and without an
18 ga. steel barrier suspended 60″ below the floor slab. Shown are laboratory
versus field measured values.
Phase I: Above-Ceiling Work
Several correction measures were recommended for above the Quiet
Room ceiling. The first was to reduce the number of isolators that
support the ceiling from 100 to 72 by strategically removing isolators
to make the spacing as even as possible. The second was to increase
the loading across the ceiling plate by installing two layers of 1.6 cm
(5/8″) drywall cut to fit the cavities formed by the angle iron framing,
in addition to a viscoelastic damping adhesive. Third was to overlay
the entire ceiling with 10 cm (4″) of mineral wool sound absorption
batts. The insulation adds additional weight across the ceiling plate,
and introduces sound absorption to the above-ceiling cavity. The
added mass and absorption reduces the mass-air-mass resonance of
the double wall system and thereby increases the STL performance of
the floor-ceiling [See the Appendix] [7]. The added absorption also
reduces sound passage through this cavity which serves as a return air
plenum for ventilating the Quiet Room.
With the added weight of the drywall, damping, and insulation, plus
the reduced numbers and reconfiguring of the spring hangers, the
estimated total average loading per isolator is 72 kg (159 lb). This
loading is both greater than the pre-compression setting of 60 kg (133
lb) and yet below the maximum hanger capacity of 101 kg (222 lb)
[Refer to the Appendix].
The increased loading on each spring hanger was expected to
overcome the pre-compression short-circuiting and allow the barrier
ceiling to fully decouple from the MER floor above. The increased
hanger loading was also expected to produce an average deflection of
1.8 cm (0.7″) in the isolator springs, which should produce a vibration
isolation efficiency of 98% at 30 Hz, the lowest frequency of interest
as determined from vibration measurements on the floor and structural
steel. This degree of isolation efficiency tells us that the spring hangers
will no longer compromise the double-wall STL performance of the
floor/ceiling assembly [Refer to the Appendix] [8] [9].
Figure 10 shows the previously mentioned STL performance of the
existing floor-ceiling construction between the MER and Quiet Room
compared against the expected double wall STL for that assembly
empirically determined using laboratory measured STL values for
each individual element of the construction.
Also shown as a third curve is the estimated STL of the improved
floor-ceiling construction after installation of the following
recommended improvements:
1. The steel panels are overlaid with 2 layers of 1.6 cm (5/8″)
drywall attached using a vibration damping adhesive.
2. The number and spacing of existing spring hangers are reduced
and reconfigured to overcome the pre-compression condition.
3. The drywall-backed ceiling panels are overlaid with a 10 cm
(4″) thick layer of mineral wool acoustical absorption material.
Another recommendation was to remove the rarely (if ever) used
monorail and hoist from the Quiet Room (see Figure 5), including all
of the steel elements that originate at the underside of the MER floor
deck above (see Figure 6). This would remove a second major path of
structure-borne noise that gets induced into the barrier ceiling plate as
well as eliminate a source that radiates this structure-borne noise
directly into the Quiet Room.
Phases II & III: Mezzanine Floor Deck Isolation
As of this writing, the Phase I: Above-Ceiling Work was completed.
Subsequent work is planned and will be divided into phases. Phase II
consists primarily of using a masonry saw to cut through the entire
floor slab and deck parallel and close to the upper web of the main
floor-supporting beam along the column line at two locations. This
saw cutting is expected to create a 1.2 cm (0.5″) gap in the floor deck
to interrupt structural-borne noise (vibration) induced in that floor
slab by the low temperature chiller compressors and electrical
switchgear which both rest directly atop the slab without any
deliberate means of vibration isolation. This excitation travels
through the floor slab and radiates as airborne sound into the ceiling
cavity above the Quiet Room. Levels of compressor and switchgear
noise measured in this cavity are higher than expected when
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6. compared against the levels of airborne noise from the compressors
and switchgear measured in the MER directly above the Quiet Room,
adjusted for the noise reduction of the floor slab. The result is that
these paths for structure-borne noise are significant contributors to
the noise that intrudes into the Quiet Room and ultimately, create a
limitation for the degree of improvement that the Phase I: Above-
Ceiling Work can provide.
Figure 10. This graph shows a comparison of the third-octave band STL
performance of a 6″ concrete floor slab with an 18 ga. steel barrier suspended
60″ below the floor slab, as well as the improvement in STL expected from
the addition of drywall and cavity absorption.
Phase III is scheduled to be done should noise measurements made
after Phase II (saw cutting the floor deck) show that structure-borne
noise conduction through the structural beams supporting the MER
floor deck continues to create excessive Quiet Room noise levels. The
recommended method for interrupting these structural paths is by
temporarily jack-supporting the ends of each of ten (10) W-27 beams
that support both sides of the MER floor deck (See Figure 11), cutting
away the structural connections of those beams from the W-36 main
beams on column lines that support those beam ends, and adding
structural steel seats that allow each beam end to be supported by a
pair of steel spring vibration isolators (See Figure 12).
Residual Flanking
The vibration isolation of the MER floor deck described above under
the Phase II and Phase III renovation work will be subject to some
degree of limitation due to structure-borne noise flanking through
paths that could not be interrupted. This includes the two main
structural beams and structural concrete block walls along column
lines 9 and 10. (See Figure 11)
Figure 11. Conceptual drawing of the 10 beam ends that would need to be cut
free of the main beam support and then re-supported using two vibration
isolating springs.
Post-Renovation Measurements
Measurements of the noise levels in the Quiet Room were made
following completion of the Phase I: Above-Ceiling Work. Figure 13
shows the results for various MER equipment operation conditions.
These results show that the work done above the Quiet Room ceiling
was effective at reducing the noise intrusion of both the electrical
switchgear and the refrigeration compressors on the background
noise levels in the Quiet Room. These renovations reduced the Quiet
Room noise levels from NC-35 with the compressors operating and
NC-24 without (leaving only the switchgear noise) to NC-24 and
NC-15 (respectively). It should be noted here that the above-ceiling
renovation work also reduced the noise of the HVAC system serving
the Quiet Room, but this was neither a requirement nor specified as a
goal of this work since it can be readily turned off if needed for
low-level acoustic measurements.
Follow-up measurements after implementation of the improvements
being considered for Phases II & III (vibration isolation of the MER
floor deck) are planned once that work is completed and will be
reported in a subsequent paper.
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7. Figure 12. These sections illustrate the re-support of each W-27 beam end
from the main W-36 beams using a pair of spring isolators.
Figure 13. Quiet Room noise levels measured after completion of the
above-ceiling work (Phase I Renovations). This shows that the NC 15 target
background noise level is now met with the switchgear alone active, and that
the room noise level with the compressors operating are significantly lower
although still above the NC15 target.
Summary/Conclusions
Conclusions of this study are that provisions originally intended to
isolate the Quiet Room from electrical and mechanical equipment
operating in the mezzanine floor deck were not sufficiently designed
and were poorly installed. This combination resulted in excessive
amounts of airborne noise being transmitted into the Quiet Room.
Recommended corrective measures included removal of a monorail
beam and hoist, and enhancement of the Quiet Room ceiling to add
mass, recovery of the vibration isolation of that ceiling from the floor
deck above, and improvement of the sound transmission loss
performance of the combined floor/ceiling assembly. These
improvements were found to be highly effective at reducing
background noise levels in the Quiet Room.
Additional changes to further isolate structure-borne noise including
interrupting both the mezzanine floor deck and structural steel that
supports that deck have also been recommended for future phases of
the Quiet Room noise reduction improvement project.
References
1. International Standard, “Acoustics - Determination of sound
power levels of noise sources using sound pressure - Precision
methods for anechoic and hemi-anechoic rooms,” ISO 3745,
second edition, December 2003
2. Duda, John “Basic Design Considerations for Anechoic
Chambers,” Noise Control Engineering, Vol. 9, No. 2,
September 1977 doi:10.3397/1.2832070
3. Mason Industries, Hauppauge, NY
4. Noise criteria as defined by the American Society of Heating,
Refrigerating, and Air-Conditioning Engineers (ASHRAE) in
the ASHRAE Handbook
5. American Society for Testing and Materials ASTM E 336-10
Standard Test Method for Measurement of Airborne Sound
Insulation in Buildings
6. Wentzel, R. and Saha, P., “Empirically Predicting the Sound
Transmission Loss of Double-Wall Sound Barrier Assemblies,”
SAE Technical Paper 951268, 1995, doi:10.4271/951268.
7. Handbook of Acoustical Measurements and Noise Control, 3rd
Edition, page 31.10 Cyril M. Harris, McGraw Hill ISBN 0-07-
026868-1, 1991
8. Ibid, page 27.4
9. Noise Control in Buildings: A Practical Guide for Architects and
Engineers, Chapter 9 Part 2 Cyril M. Harris, McGraw Hill ISBN
0-07-028887-8, 1994
Contact Information
Richard A. Kolano, P.E.
INCE Board Certified
Principal Consultant
Kolano & Saha Engineers, Inc.
3559 Sashabaw Road
Waterford, MI 48329
248-674-4100
RAKolanoPE@KandSE.com
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8. Acknowledgments
The author gratefully acknowledges the efforts of Jeremy Bielecki, a
Senior Project Engineer with Kolano & Saha Engineers, Inc., who
conducted and analyzed the measurements in this project, skillfully
plotted the results, drew the CAD drawings employed for figures, and
gave this manuscript a critical reading. You are the best!
Definitions/Abbreviations
δ - Static deflection, in cm (inches)
fn
- Natural resonant frequency of a deflected spring isolator, Hz
fmam
- Mass - air - mass resonance frequency of a double wall
assembly, Hz
NR - Noise Reduction, which is simply the difference in third-octave
bands between the sound pressure level measured in the source room
and that measured in the receiving room, in dB
STL - Sound Transmission Loss, in dB
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9. APPENDIX
The Quiet Room ceiling was originally built using 100 spring isolators to support the weight of the ceiling from the underside of the Mechanical
Equipment Room floor deck above. Figure A1 shows the original (“as-built”) layout of the isolators. Also shown is the supply air ductwork that
serves the Quiet Room. The layout of this ductwork as well as the dimensions of the angle iron grid both influenced the original spacing and
placement of the isolators.
Figure A1 includes a color coding of the existing, originally installed spring isolators to indicate which of those isolators should be removed and/or
relocated to create a more equal distribution of the ceiling weight across the array of isolators without creating excessive spans for the angle iron grid
which supports the ceiling panels and without under loading or overloading any given isolator.
Figure A1. Quiet Room Ceiling Isolators Color Code (Before):Green =
Existing, to RemainBlack = Existing, to be RemovedRed = Pairs of Existing
Isolators to be Removed and Replaced with a Single Isolator
Figure A2. Quiet Room Ceiling Isolators Color Code (After):Green = Final
Layout after Excess Isolators are Removed or Repositioned
Figure A2 shows the revised isolator layout that was developed based upon maintaining the original angle iron grid, the added weight of the
additional drywall and insulation, and the need to increase the average loading of the isolators to something greater than the pre-compression loading.
This approach resulted in the use of 72 isolators to support the ceiling with the increased loading.
With 72 isolators and a total improved ceiling weight estimated to be 5179 kg (11,417 lb) (± 10%), each isolator will support 64 to 79 kg (142 lb to
174 lb) or about 72 kg (159 lb) on average and produce a static deflection of 1.8 cm (0.7″). Since the rated capacity of each existing isolator is 101 kg
(222 lb), a 60% pre-compression of the isolators requires a load of at least 60kg (133 lb) to overcome the pre-compression.
The mass - air - mass resonance frequency (fmam
) of a sealed double wall system establishes the frequency at which double-wall sound transmission
loss performance begins to be achieved. The fmam
of a double wall system can be determined using the following equation [7]:
Where fmam
= mass-air-mass resonance frequency, Hz
m1
= surface mass of the first wall, kg/m2
m2
= surface mass of the second wall, kg/m2
d = separation between the two walls, mm
K = 60 for an empty cavity; 43 for a cavity filled with sound absorptive material
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10. In this case, the fmam
for the original floor-ceiling assembly is expected to be 10 Hz. With the improvements described here-in, the fmam
of the
floor-ceiling is reduced to 7 Hz. This assumes that air alone is the only element that acoustically couples the two masses, and that there is no absorber
within the airspace. When the double wall system is actually vertically separated elements, such as the Quiet Room sound barrier ceiling suspended
below the MER floor deck, the mass-air-mass frequency is not the only consideration. Also of concern is the stiffness of the elements that structurally
support the barrier ceiling. This should also be considered, especially if the suspension system is stiffer than air. In such a case, the resonant
frequency of the suspension system would be higher than the mass - air - mass resonance frequency of the floor and ceiling, thereby limiting the
effectiveness of the double wall system for achieving high STL performance. In the experience of the author, practice has shown that the resonant
frequency of the resilient suspension system for a massive ceiling hung below a structural floor deck may create a limiting condition if that resonant
frequency is too high (i.e., above the mass - air - mass resonance frequency of the floor-ceiling system). In such a case, structure borne vibration
measured in the floor may be transmitted through the elements that are supporting the ceiling and result in sound radiation from the barrier ceiling
plane which is at a higher magnitude than would be expected simply from the sound transmission loss performance of the decoupled floor-ceiling and
the source level/spectrum of noise measured in the space above that floor. As a result, the deflection and resonant frequency of the spring hangers that
support the Quiet Room ceiling were initially a concern, and remained a concern following implementation of the recommended measures that
allowed that ceiling to “break free” from the pre-compression settings of the isolation hangers. The concern was that even with the increased ceiling
loading, and the average 1.8 cm (0.7 inches) deflection expected from the isolator springs, there may continue to be conduction of structure borne
noise through the spring hangers at low frequencies which would reduce the double-wall STL of the floor/ceiling assembly at low frequencies. Based
upon the following equation [8], the average deflection of the spring hangers is expected to produce a resonance frequency of 3.7 Hz.
Where fn
is the natural resonant frequency of the deflected spring isolator, K is a constant of 15.8 (3.13 for I-P) and δ is the deflection of the spring
isolator in millimeters (inches).
This average spring deflection is also expected to produce a vibration isolation efficiency of greater than 98% at frequencies above 30 Hz, which is
the lowest frequency of interest as determined from vibration measurements on the MER floor and structural steel. This isolation efficiency is based
upon the following equation [9]:
Vibration Isolation Efficiency
Where fd
is the frequency of the disturbance which is to be isolated and fn
.is the natural resonant frequency of the spring isolator.
With vibrational energy passage through the spring hangers reduced by 98% (or more), any reduction in the double wall STL due to structure borne
noise transmitted through the spring hanger becomes negligible. This agrees with our standard practice of assuring that any resonant elements which
potentially couple the opposing sides of a double wall assembly be selected so that the natural resonant frequency of those elements are below (less
than) the fmam
of the double wall assembly.
The Engineering Meetings Board has approved this paper for publication. It has successfully completed SAE’s peer review process under the supervision of the session organizer. The process
requires a minimum of three (3) reviews by industry experts.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or
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ISSN 0148-7191
http://papers.sae.org/2015-01-2348
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