Hrb electromech,111116

Moustafa M. Elsayed, Doha (12/9/2006) 1
What you need to know about
Designing
Electro-Mechanical Systems
for
High-Rise Buildings
By
Dr. Moustafa M. Elsayed
Consultant
moustafa.elsayed@egec-xprt.com

Contents
• Definition of a High-Rise Building
• Introduction
• Design Requirements
• Stack Effect
• Core Design, Location and Components
• Floor-to-Floor Height & Raised Floor
Option

Moustafa M. Elsayed) 3
Contents
• Electric & Communication
Closets
• Building Orientation
• Insulation and Heat Stores
• Fire Scenario
• Fire Fighting Strategy

Super High Rise
Building
Shimizu Super Highrise
(SSH)
Shimizu Corp. (Japan)

Definition of a High-Rise Building

Definition of a High-Rise
Building
The International Building Code (IBC 2000)
and the Building Construction and Safety Code,
NFPA 5000TM-2002, define high-rise buildings
as:
A structure more than
22 m (75 feet ) high

A Strategy for Dublin Building Height,
proposed four height thresholds
Low-rise - up
to 15m
Mid-rise - 5 to
50m
High-rise -
50 to 150m
Super high-
rise - above
150m

The ASHRAE Technical Committee for
Tall Buildings, TC 9.12
one whose height is greater than 300 feet
(91 m).

The Council on Tall
Buildings and Urban
Habitat (CTBUH)
one in which the
“tallness” strongly
influences planning
design or use.

The General Services Administration (GSA) in USA
sponsored the “International Conference on Fire
Safety in High-Rise Buildings” in Warrenton,
Virginia, on April 12, 1971. That conference arrived at
a more complex and more flexible definition that is
appropriate. It stated:
A high-rise building is one in which emergency
evacuation is not practical and in which fires must
be fought internally because of height.

Introduction
The tall commercial
office building only
became possible
through the
invention of the
elevator safety
braking system by
Elisha Graves Otis in
1853.

Introduction
• High-rise = high-risk
• All high-rise building design will require
performance-based (engineered) fire and
life safety design
• The fire resistance of the structure, to
larger and longer duration fires, will be a
consideration

Introduction
• Every year there are about 7,000 fires that
break out in high rise office buildings
causing deaths, injuries and millions of
dollars in fire damage. Most of these could
be eliminated if everyone practiced good
fire prevention on the job and planned
ahead for a fire emergency.
• Construction material and fire proofing
material will get extra attention

Design Requirements
Symbols of power,
prestige, wealth,
success, and national
pride.
Buildings, and their
occupants, as safe and
secure as possible.

Design Requirements
• Life safety
• Smart security
• More bandwidth, smarter buildings.
• More hours of operation, along with more
electrical capacity, fiber optic access, and
heating and air conditioning capacity.
• Energy efficient building

Design Requirements
• Efficient vertical
transportation
• Smart mechanical systems
• Building infrastructure must
be well planned to attract
tenants
• Easy upgrades and retrofitting
to accommodate future
technologies.

Stack Effect
Stack
effect
Reverse
stack
effect

Stack Effect

Stack
Effect

Stack Effect: Problems
Elevator doors’
failure to close
properly

Stack Effect: Problems
Heating / Cooling
Problems

Stack Effect: Air Entry Points
• Entry doors & doors that
open to truck docks
• Any outside air intake or
exhaust
• Louvers that are provided in
the building

Stack Effect: Air Entry Points
• Overhangs in the construction
with light fixtures that are located
immediately above the ground
level and are not properly sealed
against leakage.
• and any possible small fissures in
the exterior wall itself.

Stack Effect: Internal Passages
• Fire stairs
• Elevator shafts
• Mechanical shafts for ducts and
piping
• Any other vertical penetrations
that exist at the edge of the
floor slab at the exterior wall or
for pipes.

Means to Minimize Stack Effect
• Use tight exterior wall
• Vestibules or air locks for loading docks,
with good door seals, or use of revolving
doors
Minimizing Infiltration from Outside

Minimizing Infiltration from Outside
• Use Supply at least 5% outside air
than exhaust to ensure
pressurization tight exterior wall
• Close all shafts & seal all
penetrations

Means to Minimize Stack Effect
Minimizing Internal Air Flow
Using doors at the
entry of elevator
banks
Stairs are to be
interrupted with
doors

Core Design
•The core design should meet the
needs of the occupants while
also simplifying the provision of
mechanical and electrical
services to the occupied floor
•The cost of the core and its
content can be substantial.

Core Design
• The configuration of the core should be
arranged in the tightest area possible,
resulting in the most efficient possible
use of the floor.

Core Location
Central Core
• Maximum flexibility in the architectural
subdivision of the floor
• Potential to improve the distribution of air-
conditioning ducts
• Simplify the construction of the building

Core Location
Multiple Cores
• In buildings with very large floor plates,
multiple cores may be necessary to reduce
the travel distance to stairs or toilets.
• A cost disadvantage of multiple cores is
the potential need for additional elevators,
although this is not always necessary.

Core Components
•Fire stairs
•Vertical transportation elements: passenger
elevators and one or more service or freight
elevators
•Toilet rooms for both the male and female
•Electric closets
•Communication closets for multiple
telecommunication providers

Core Components
• Local fan rooms or large supply air and
return air shafts
• Shaft space for other HVAC risers, such as
toilet exhaust, general exhaust, or dedicated
smoke exhaust risers and possibly kitchen
exhaust risers

Core Components
• Space for risers for the piping of the HVAC
system and plumbing system as well as riser
space for electrical distribution cable and
distribution cable for the building
management and fire alarm systems.

Core Area
• The definition of an efficient core is not simple
in that the percentage of the gross area that
will be used is very much a function of the size
and the usage of the floor.
• For example, on larger floor plates, i.e., those
with areas greater than 20,000 gross ft2 (1,800
gross m2), it is a core that often will take less
than approximately 15 to 20 percent of the
total floor area of a given floor.

Core Area
• If a floor grows beyond a certain size or has
internal loads with high cooling requirements
it can become necessary to add a second local
floor air-handling unit and fan room, which
will cause a reduction in the usable area.
• Moreover, on smaller floor plates, the core
may take as much as 30 percent of the total
floor area.

Example of a Core Design

Floor-to-Floor Height
The overall cost of a tall building
is affected by the floor-to-floor
height of the individual floors.

An increase in the floor-to-floor height will
increase the surface area of the skin of the
building, the length of the vertical structural
elements as well as all of the building’s other
vertical elements, such as shaft enclosures,
HVAC, plumbing, electrical power
distribution and telecommunication risers,
elevator components, stairs, and the length of
the interior partitions.

• Where zoning regulations exist that limit
the bulk and height of a building, a small
increase in the vertical dimension of each
floor may result in fewer floors in the
developed building.
• The final floor-to-floor height of the
office occupancy floors of any building
will involve decisions by the owner,
architect, structural engineer, and both
the HVAC and electrical engineers.

Raised Floor Option
The need to satisfy the expanding and
continually changing electronic needs in the
tall commercial building has forced
consideration of the inclusion of a raised
floor to handle the horizontal distribution of
both power wiring and information
technology cabling, which includes both the
telecommunication cabling and any
interconnection of personal computers,
printers, and the like.

Raised Floor Option
Typically the raised floors in
general office occupancies will
be between 4 and 6 inches (100-
150 mm) above the concrete slab
when the raised floor is used
exclusively for the distribution
of power wiring and
information technology cabling.

Raised Floor Option
• Floor tiles are included above the slab to
provide the walking surface in the office space,
which in turn are covered by carpet tiles of the
same size as the floor tiles.
• The carpet tiles and then the floor tiles can
easily be lifted to provide the needed access to
allow modification of the wire and cable as
changes evolve in the needs of tenants.

Raised Floor Option
One cost benefit that resultes to projects using a
raised floor exclusively for wire and cable
distribution is that neither the wire nor the cable
installed within the raised floor cavity need be
plenum rated or installed in conduit.
Nonetheless, the application of raised floors with
under-the-floor air-conditioning distribution
systems is becoming more common with the
increased use of raised floors.

Raised Floor Option
The use of a raised floor allows the
relocation of electric outlets and
information technology connections at a
relatively low cost when compared to the
cost of these relocations without a raised
floor.

Raised Floor Option
The inclusion of the raised floor will increase
the floor-to-floor height, but the integration of
a raised floor with an under-floor air-
conditioning distribution system may
minimize, if not eliminate, the increase in the
floor-to-floor height for a given project.

Conclusion

Floor-to-Floor Height: Conclusion
• The floor-to-floor height of a tall commercial
office building can usually be of 3.8 m 4.1 m.
• See Figure 1-6.
• The space from the bottom of the ceiling to
the top of the slab of the floor above is 1.2 m.

Floor-to-Floor Height: Conclusion
• This 1.2 m space would contain the lighting
fixtures, ducts, sprinkler piping, and
structural steel system supporting the slab.
• An increase (or decrease) in any of the
elements shown in this figure will result in an
increase (or decrease) in the floor-to-floor
height.

Electric Closets
• Location: to permit diverse routing to any
area of the floor to meet the design
criterion, in watts per square foot.
• There are limits to the distance that the
floor distribution cable can be extended on
any given floor without a cost penalty.

Electric Closets
• On a floor in excess of approximately
25,000 ft2 (2,400 m2), more than one
electric closet will be required to serve
that floor.
• On floors smaller than 25,000 ft2 (2,400
m2), a second closet may still be included
to meet the possible future expansion
needs

Communication Closet
• The communication closet has gone through
a major series of changes over the past
decade.
• Originally the closet was called a telephone
closet, but that terminology is rarely used
today.
• The appropriate terminology is
“telecommunication,” “communication,” or
“information technology” closet.

• Traditionally, the closet contained the vertical
telephone riser cables that in turn connected to
telecommunication terminal blocks from which
the horizontal runs on the specific floor were
extended by the telephone company to the
user’s phone.
• However, that was in a time when there was
only one telephone company and no such thing
as a computer.

The communication risers may not be installed
during construction, just the riser space and
empty sleeves in the communication closet,
with the empty risers being filled as specific
tenants request specific telecommunication
providers for their space.

In the below-grade levels, space will be
needed for multiple points of entry from each
telecommunication provider to allow its
service to be brought to two separate service
rooms from at least two different streets to
ensure continuity of service under any
possible emergency contingency.

Building Orientation
• Tall buildings are exposed to
the full impact of external
temperatures and radiant
heat.
• The overall building
orientation has an important
bearing on energy
conservation.

Insulation and heat stores
• Good thermal insulation of the building skin
reduces heat transfer, both from solar gain and
loss of coolness from the inside.
• A second skin (a rain wall) can be built over
the inner wall with an air gap in between.
• Structural building mass may be used to store
heat.

Insulation and heat stores
• In temperate climates, structural and
building mass can absorb solar heat during
the day and release it at night. A water-
spray system on hot facades promotes
evaporation and therefore cooling.
• Also in temperate regions, solar windows or
a solar-collector wall can be located on the
outer face of the building to collect the sun's
heat.

Fire Scenario :
One Meridian Plaza Fire
• In 1991 a fire on the 22nd
floor of the 38-story Meridian
Bank Building (Philadelphia)
took place for more than 19
hours.
• It was the largest high-rise
office building fire in modern
American history

Fire Scenario :
One Meridian Plaza Fire
• Completely consuming eight
floors of the building
• Fire was controlled only
when it reached a floor that
was protected by automatic
sprinklers.

Fire Scenario : VENTING
• Sealed or locked windows
(High-rise buildings may
be considered windowless
buildings)
• Risk of venting by
breaking thick glass
windows

Fire Scenario : VENTING
• Large volumes of heat and
smoke generated by the
fire become trapped in the
structure.
• This giant smoke cloud,
spreads throughout the
sealed high-rise building.

Fire Scenario : Stack Effect
• The so-called "stack effect" causes smoke
to spread up or down many floors during
a fire in a high-rise.
• The uncontrollable smoke movement
caused by the stack effect is another
reason window venting is ineffective
during a high-rise fire.

Fire Scenario : HVAC SYSTEMS
• HVAC systems in some HRB are not fire-
resistive
• Ducts, shafts, and poke-through holes
penetrate fire-resistive floors, walls, and
ceilings
• A high-rise hotel fire in Las Vegas, Nevada,
spread fire and smoke through the central air-
conditioning system and killed 85 people in
rooms on upper floors.

• The air system was not equipped with smoke
detectors arranged to shut down the system
during an emergency.
• The fire dampers-shutters designed to stop
spread of fire in ducts and shafts of the air-
conditioning system--did not close properly.

• Smoke, heat, and flame were pumped
throughout the so-called fire-resistive hotel by
the air-conditioning system.
• Firefighter's battling a fire in a high-rise
building depend on the building systems for
success in extinguishments.

Fire Scenario : Service Systems
• The elevator system must take them, tools, and
equipment up to the fire.
• The standpipe system must provide water pressure
and volume to the upper floors.

Fire Scenario : Service Systems
• A building communication system must
allow fire department firefighting radio
transmission in these steel skyscrapers.
• If any of these building systems fail or
are not present, firefighters will be
unable to extinguish the fire.

Fire Scenario : Elevators
It is important to note that elevator shafts,
like stairwells, are vulnerable to smoke
contamination as well.

Fire Scenario : Elevators
Due to both the Stack effect and the
Breaking-of-the-Seal effect, smoke
penetrates into both the elevator
carriages and shafts during a fire.
Additionally, when elevator carriages are
forced to make stops on smoke filled
floors, both the elevator shaft and the
carriage itself can quickly become
contaminated beyond usable limits.

Fire Fighting Strategy

• At a low-rise building fire, strategy can be
to extinguish the fire and evacuate the
people at the same time.
• HRB people evacuation
• HRB defend in place strategy

Impacts on Fire Engineering
• Performance of people trapped in a burning
high-rise building
• Firefighting strategies for HRB:
from inside stairways.
an interior attack.

Impacts on Fire Engineering
• Firefighters must extinguish the fire using
handheld hose streams advanced through heat
and smoke from an inside stairway. If this
method fails, there is no alternate plan. An
outside attack is not an option.

• A defend-in-place strategy depends on two factors:
that the building has the ability to contain fire to a
particular area and that the occupants will obey the
fire chief's instruction to stay in place.
• Neither of these assumptions is necessarily true.
High-rise buildings are not fire resistive, and people
leave the high-rise buildings during a fire regardless
of instructions to do otherwise.
• Experience showed that "the 'defend-in-place‘
strategy does not exist."

• The only real fire protection for a high-rise
building is
an automatic sprinkler
a smoke-removal system

Smoke Management: Objectives
• To remove smoke from the area within
which a fire has developed
• To maintain smoke-free areas that will
allow the occupants to exit the building
without being subjected to the smoke
generated by the fire.

Methods of Smoke Control
Objectives
To control the movement of smoke in case of
fire in order to facilitate the protection of the
occupants and properties in the building.
To help firefighters to accomplish their job.

Compartmentation
Dilution
Pressurization

Compartmentation
Compartmentation is to use barriers with
sufficient evidence to remain effective
throughout a fire exposure. These barriers
provide protection against fire spread.
Barriers like walls, partitions, floors, doors,
....etc, provide some level of smoke
protection to spaces remote from the fire

Dilution Remote from Fire
This is used to maintain acceptable gas and
particulate concentrations in a compartment
subject to smoke infiltration from an
adjacent space.
Dilution can be effective if the rate of smoke
leakage is small compared to either the total
volume of the safeguarded space or the rate
of purging air supplied to and removed from
the space.

Methods of Pressurization of
Stairwell
To provide smoke-free
escape route in the event
of building fire
To provide smoke-free
area for fire fighters.
Objectives

Methods of Pressurization of Stairwell

Pressure Sandwich

Testing of Smoke Control Systems
Initial Testing
To assure that the system is operated as
designed
Possible problems :
fans operate backward
no electric power is supplied to fans
controls do not work properly . . . etc.

Testing of Smoke Control Systems
Regular Testing
Measure pressure differences at
pressurization
Measure air flow velocity from stairwell
through doors to various spaces

Computer Based Security Systems

Intrusion Detection System
• Some minimum requirements:
– Entrance to each office door
– Motion detection in each office
– Foyer motion detectors
– CCTV in each foyer, lobby, and parking
area.

Access Control System
Areas requiring
medium level
access security will
be controlled by the
access card,
keypad with
memorized pass-
number &
fingerprint
verification.

Television Systems

Card Reader Biometrics
Door Alarm
Live Camera
Feeds
Card Reader
Database
Door Alarm
Database
Biometrics
Database
SmartCatch
Vision
Central Matrix Switch
ALERTS
RULES
Card Reader
signal

Security Guard Patrol System
• Conduct scheduled fire and security
patrols.
• Guards patrol all floors throughout day
and night.
• Record guards movements with access
reader.
• May find problems with communications
due to steel buildings.
• Can use intercom system

Fire Control System
Fire Detection
&
Alarming
Automatic Fire
Fighting: Sprinklers

Fire Alarm: Survivability Requirements
The Code requires that all circuits
necessary for the operation of the
notification appliances be protected until
they enter the evacuation signaling zone
that they serve. Any of the following
methods meet the survivability
requirements:
• A two-hour rated cable or cable system
• A two-hour rated enclosure
• Performance alternatives approved by the
Authority Having Jurisdiction.

Emergency telephone stations are
positioned at every floor throughout the
building to enable fire department
personnel to communicate freely in their
fire fighting efforts.
The emergency phone system provides
two-way communications throughout the
entire facility
Fire Alarm Fire Fighters
Telephone Systems

This is to enables occupants to safely
escape the building in the event of a power
failure.
This must be equipped with back up
batteries capable of powering exit and
emergency lights for more than an hour
In high rise buildings emergency lights
should be connected to the building fire
alarm system.
Emergency Lights

Emergency Power
The building should have an emergency
power generator.

Air
Conditioning
Systems

Air-Conditioning System Alternatives
• All-Air Variable Air Volume (VAV)
Systems
Alternative types of VAV boxes
Low Temperature Air VAV Systems
• Air-Water Systems
• Underfloor Air Systems

Variable Air Volume Constant Air Volume

Underfloor Air Systems

Air Distribution Alternative Systems
Alternative 1
Central Fan Room
Alternative 2
Floor-by-Floor Fan Rooms with Chilled
Water Units
Alternative 3
Floor-by-Floor Fan Rooms with Direct
Expansion Units

Alternative 1—Central Fan Room
• Multiple AHU systems in one or more
room
• Supply air delivered into a common
discharge header from all of the supply
systems
• Vertical risers in two-hour fire-rated
shafts within the core of the building
• At each floor: horizontal duct taps with a
fire damper

Alternative 2—Floor-by-Floor Fan
Rooms with Chilled Water Units
A local floor fan room, located within
building core
Chilled water for the cooling coil is
provided by a central chilled water plant

Alternative 2—Floor-by-Floor Fan Rooms

POINTS OF COMPARISON OF
ALTERNATIVE SCHEMES
• First Cost
• Construction Schedule Impact
• Owner Issues
• Equipment Considerations
• Architectural Issues

Central Heating and Cooling Plants
Design Factors
• Weight, space requirements, and impact on
structural system.
• Effect on the construction schedule.
• Specific changes in mechanical room
detailing and slab construction within which
the equipment is located.
• Acoustical considerations.

• Ease & cost of operation and
maintenance
• Available energy sources.
• Life-cycle costs of each alternative
solution
• Space and cost considerations of a long
vertical flue from the fossil-fueled boiler

Central Plant
Locations

Acoustical Considerations
of Central Plant Locations
• Location of all equipment: allow
achievement of desired acoustical levels
in spaces above, below, or adjacent to
central plants
• Solution will involve an understanding of
characteristics of the sound generated by
equipment and alternative paths

Acoustical Considerations
of Central Plant Locations
Sound paths
• Transmission of noise itself through floors,
ceilings, and walls of mechanical space
• Vibration and noise associated with
vibration that is transmitted by building
structure to occupied areas

Chilled Water
Piping
Arrangement:
Direct Water
Pumps

Chilled Water
Piping
Arrangement:
Primary
&
Secondary
Pumps

Chillers
Location
Virtually at any
floor
Example:
70-storey, 900 foot
Open type expansion

Chillers Location
Constrains
• Standard working pressure for chillers and heat
transfer equipment: 150 PSIG (1,000kPa).
• Additional cost for higher working pressure
(None proportional).

Pressure Reduction: Alternative A
• Pump at discharge side of chiller
• Primary pumps & no secondary for chiller
circuit
• Zone H.E. with secondary pumps

Plate-and-frame
H.E
The maximum head
of each zone is 143
PSIG (986 kPa),
which is below the
threshold design
pressure of 150
PSIG (1000kPa)

The Economics Of Temperature
Differentials
• Small buildings
– a 10°F or 12°F DT in the chiller
– a 10°F DT or 3 gpm per ton for the condenser.
• HRB: capital costs of the piping, valves, and
fittings can be substantially reduced, with a
possible penalty in refrigeration machine
operating cost, by using larger DT with a lower
flow of water

Conclusion
Higher DT in both the chiller and
condenser is worthy of evaluation, as
there can be significant savings in cost
of piping, fittings, and valves
The Economics Of
Temperature Differentials

Fire Safety Problem
A high-rise building is one in
which emergency evacuation is
not practical and in which fires
must be fought internally because
of height

Design of Life Safety Systems
• Architect
• Structure design engineer
• HVAC design engineer
• Electrical design engineer
• Fire fighting design
engineer

Components of Fire Management System
• Detection system
• Fire standpipe and automatic sprinkler
systems
• Smoke management system
• Emergency electric power system
• Automatic elevator recall system
• Communication and alarm notification
systems
• Central fire command center.

• In return air connection on each floor
• Downstream of filters in each supply
system
• Ceiling of each elevator lobby
• Mechanical equipment rooms
• Transformer and telephone equipment
rooms,
• Similar spaces unless room is protected
by an automatic suppression system such
as sprinklers.
Smoke Detectors Locations

Control Network

Internet BMS

Definition of
Building Commissioning -1
Commissioning is a
quality assurance
process of
the installation of the
systems in a building.

Definition of
Building Commissioning -2
• It is a process for achieving,
verifying and documenting the
performance of each system to
meet the operational needs of the
building within the capabilities of
the documented design and
specified equipment capacities,
according to the owner’s
functional criteria.

Definition
of
Building
Commissioning -3
Successful
commissioning
includes the preparation
of manuals and training
of operation and
maintenance personnel

The definition refers to the building as a total
system, which includes the structural
elements, building envelope, life safety
features, security systems, elevators,
escalators, plumbing, electrical, controls, and
the HVAC.
Definition of
Building Commissioning - 4

Advantages of Building
Commissioning
Open channels of communication.
Create a better understanding of design
intent.
Provide early assignment of
performance responsibilities.
Set performance goals such as
energy, environment, and life cycle.

Commissioning
Establish continuous monitoring of
priorities and schedules.
Improve operation and maintenance
programs.
Improve quality of operator personnel
training.

Reduce callbacks
and assist in
dealing with
warranty claims.
Enable owner to
recognize system
capabilities and
limitations
Commissioning

Commissioning Team
Commissioning authority
( qualified professional company or agency
that implements the overall commissioning
process )
Owner
Design professionals

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