ASHRAE Standard 62.1 Update
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ASHRAE Standard 62.1 Update

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Dennis Stanke of Trane presents ASHRAE Standard 62.1 Update. Dennis is the Chair of the Standard 62.1 committee. Presented at the 2008 ASHRAE Region VI CRC in Chicago, Illinois....

Dennis Stanke of Trane presents ASHRAE Standard 62.1 Update. Dennis is the Chair of the Standard 62.1 committee. Presented at the 2008 ASHRAE Region VI CRC in Chicago, Illinois.
May 15, 16, 17, 2008

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  • Great presentation and giving good ideas and knowledge to every on about standards of IAQ and their solutions thanks for great stuff. Indoor air quality (IAQ) affects the prevalence of several very common health effects including communicable respiratory illnesses such as common colds (e.g. rhinovirus infections), influenza, adenovirus infections, and measles; allergies and asthma; and acute nonspecific health symptoms often called sick building syndrome symptoms. These health effects lead to health care costs plus the costs of sick leave. Again Thanks
    http://www.paragoncontrols.com/leed_green_CostOfPoorIAQ.aspx
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  • Step 1: Vot = Voz = Vbz = 7.5*65 + 0.06*1000 = 547.5 at design at population Step 2: Vat = 0 + 0.06*1000 = 60 at zero population Step 3: Cr-max = Co + 0.0105*65/550 = 0.000400 + 0.001240 = 0.001640 at design population and design OA Step 4: Max signal when Cr = Cr-max or  C-max = 1240 ppm, and min signal when Cr = Cr-min or  C-min = 0 Step 5: Adjust damper so Vot = Vot-des at max signal, Step 6: Adjust damper so Vot = Vot-min at min signal
  • The space requires Vot = 60 cfm @ Pz = 0, Vot = 547.5 cfm @ Pz = 65. If Co = 400 ppm, then indoor concentration ranges from 400 to 1640, and  C ranges from 0 to 1240. With the Users Manual approach, the controller simply adjusts the outdoor-air intake proportionally between 60 and 550 cfm, as Ci varies between 400 and 1640 (or  C varies between 0 and 1240). This equation defines outdoor air intake flow as a function of indoor CO2 concentration. m = (547.5 - 60)/(1640 - 400) = 487.5/1240 = 0.393 b = Vot - m*Crz = 547.5 - 0.393*1640 = - 97 Vot = 0.393*Crz – 97 (assuming a constant Co = 400 ppm) or m = (547.5 - 60)/(1240 - 0) = 487.5/1240 = 0.393 b = Vot – m*(Crz – Co) = 547.5 - 0.393*1240 = + 60 Vot = 0.393*(Crz – Co) + 60 (assuming Co = unknown)
  • If you do these steps, the result of maintaining  C (see Article #5) will be a Vbz level somewhat higher than the required minimum. “Using a spreadsheet at each given zone population, we assumed an initial value for zone CO2 level ( Cr ), solved Equation 8 for intake airflow, then solved Equation 2 for the differential CO2 expected for the given zone population and calculated intake airflow. This process was repeated until the expected CO2 level matched the initially assumed level.” Vbz = 0.393 · ( Cr – 400) + 60 (8) ( Cr – Co ) = Pz*k*m/Vbz = Pz*8400*1.25/Vbz = Pz*10,500/Vbz (2) So, if Co = 400 and Pz = 30, what will we sense for  C and what will we find for Vbz? Solve equations repeatedly, first assuming initial  C-int value, then using Vbz from Eq 8 to find  C. Repeat until  C-int =  C. If  C-int = 1200, Controller would find Vbz = 0.393*1200+60 = 529, so  C = 30*10500/529 = 495, so 1200 was too hi If  C-int = 1000 ppm, Controller would find Vbz = 0.393*1000+60 = 451, so  C = 30*10500/451 = 698, so 1000 was too hi If  C-int = 800 ppm, Controller would find Vbz = 0.393*800+60 = 373, so  C = 30*10500/373 = 845, so 800 was too lo If  C = 850 ppm, Controller would find Vbz = 0.393*850+60 = 392, so  C = 30*10500/392 = 803, so 850 was too hi If  C = 824 ppm, Controller would find Vbz = 0.393*824+60 = 382, so  C = 30*10500/382 = 824, so 824 was “right”
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Transcript

  • 1. ASHRAE Std 62.1 Update Where Are We Now? May 2008 Dennis A. Stanke Trane • La Crosse, WI
  • 2. ASHRAE Standard 62.1 What Is It?
    • Title: “Ventilation for Acceptable Indoor Air Quality”
    • Purpose: “… to specify minimum ventilation rates and indoor air quality that will be acceptable to human occupants and are intended to minimize … adverse health effects.”
    • Scope: All commercial, institutional, and high-rise residential buildings
    It’s the ventilation standard …
  • 3. ASHRAE Standard 62.1 Why Care?
    • It’s the basis for many ventilation codes , both now (UMC) and in the future (IMC)
    • More stringent than codes in some cases (helps establish the “ standard-of-care ”)
    • Less stringent than codes in some cases (helps designer in pursue code variance )
    • Compliance with Std 62.1- 2004 is a prerequisite for any LEED-NC credits (Sections 4 thru 7 – except Section 6.3 – or the building code)
  • 4. ASHRAE Standard 62.1 What’s Its History? 62-2001 a little more change 62-1999 a little change 62-1973 first issued 1990 2000 2010 1970 1980 62.1-2004 new VRP, many lower rates 2006 Supplement ETS separation 62.1-2007 corrections, clarifications 62-1989 higher rates 62-1981 lower rates
  • 5. what does Std 62.1 require now? Must Comply With …
    • General requirements (Sect 4 and 5)
      • To reduce generation of indoor contaminants and introduction of outdoor contaminants
    • Ventilation requirements (Sect 6)
      • To dilute and remove indoor contaminants
    • Construction, startup, operation and maintenance requirements (Sect 7 and 8)
      • To assure installation/operation as designed
  • 6. Std 62.1-2007 Section 4 Outdoor Air Quality
    • 4.1.1 Regional Air Quality. Assess regional outdoor air quality to determine NAAQS compliance status
      • Check for non-attainment for any EPA criteria contaminants
    • 4.1.2 Local Air Quality. Survey site for unusual local sources
      • Visit the site, look around
    These assessments inform air cleaning decisions
  • 7. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.1 Natural Ventilation. May use natural ventilation in lieu of or in conjunction with mechanical ventilation, provided
      • Perimeter areas are within 25 ft of outdoor opening, which is least 4% of floor area
      • Interior areas are within 25 ft of opening, and opening to perimeter area is at least 8% of floor area, not less than 25 ft 2
        • [For mixed-mode buildings, the mechanical ventilation system must comply with Section 6.0, and, presumably, the natural ventilation system must comply with Section 5.1.]
    architect Future: Needs attention, especially mixed mode and hi-rise residential
  • 8. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.2 Ventilation Air Distribution. Design to assure that ventilation air can get to occupied zones
      • Provide means to adjust ( balance ) airflows
      • Design to assure mixing in RA/OA mixing plenums
      • Document assumptions and air balancing requirements
  • 9. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.3 Exhaust Duct Location. Prevent leakage of harmful exhaust contaminants into the building
      • Design exhaust ducts to operate at negative pressure
    architect
  • 10. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.4 Ventilation System Controls. Design to assure minimum ventilation
      • Provide controls to enable [and disable ] fan
      • Maintain minimum outdoor airflow at any load condition . Note : VAV systems with fixed dampers must comply
    Requires OA flow sensing and control, or OA damper logic which responds to SA flow architect
  • 11. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.5 Airstream Surfaces. Reduce space contamination due to air distribution system
      • Use duct materials that resist microbial growth per UL 181
      • Use duct materials the resist erosion per UL 181
  • 12. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.6 Outdoor Air Intakes. Reduce contamination from outdoors
      • Locate intake a minimum distance from outdoor sources, per Table 5.2. Examples of more than 10 sources/distances:
        • Loading dock 25 ft
        • Dumpster 15 ft
        • Surface below intake 1 ft
        • Cooling tower exhaust 25 ft
      • Design to limit rain water penetration (using hood, e.g.) or manage water that penetrates
      • Use bird screens, prevent bird nesting at intake
    architect Future: Working on Addendum to improve clarity, add some sources
  • 13. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.7 Local Capture of Contaminants. Reduce recirculation of indoor contaminants
      • Exhaust locally captured contaminants (from printers, for instance) directly to outdoors
    • 5.8 Combustion Air. Reduce contaminants from combustion appliances
      • Provide sufficient combustion air
      • Provide sufficient air for removal of combustion products
  • 14. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.9 Particulate Matter Removal. Reduce rate of dirt accumulation on HVAC devices
      • Use at least a MERV 6 filter upstream of dehumidifying coils and other wet-surface devices (about 20% Dust Spot)
  • 15. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.10 Dehumidification Systems. Design to reduce dampness in buildings during mechanical cooling
      • Limit RH to 65% or less at design dew point condition without solar load
        • [Basic CV systems might not comply]
        • [System configured and controlled properly can comply]
      • Design so that intake airflow exceeds exhaust airflow
        • [Direct control of building pressure can be used to meet this]
    2007: Clarified RH limit at design dew point
  • 16. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.11 Drain Pans. Assure condensate drainage without flooding or carryover
      • Slope drain pan at least 1/8 “ per foot
      • Locate drain opening at lowest point of drain pan and size to prevent overflow under any normally expected condition
      • Use P-trap or other seal to prevent ingestion of air while allowing complete drainage with fan on or off
      • Size drain pan with length at least 1/2 coil height or as necessary to limit carryover to 0.0044 oz per sf coil per hour at peak dew point condition
  • 17. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.12 Finned Tube Coils and Heat Exchangers. Select to reduce water droplet carryover
      • Limit coil pressure drop to 0.75 in.wc .@ 500 fpm
      • Exception: No pressure drop limit when design provides access to both faces for cleaning
    • 5.13 Humidifiers and Water Spray Systems. Reduce water-borne contaminants and design to reduce carryover
      • Use potable water
      • No downstream devices within absorption distance
  • 18. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.14 Access for Inspection, Cleaning and Maintenance. Reduce dirt accumulation in air distribution system
      • Design system with adequate clearance around ventilation equipment
      • Provide doors and panels for access to ventilation equipment (air handlers, terminal units, controllers and sensors)
      • Provide doors and panels for access to devices in air distribution system (intake and mixed air plenums, coils, air cleaners, drain pans, fans, humidifiers)
    architect
  • 19. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.15 Building Envelope and Interior Surfaces. Reduce intrusion of water and water vapor and uncontrolled condensation
      • Use a weather barrier within the building envelope
      • Use a vapor retarder within the building envelope (typically on the warm side, but it really depends on wall design)
      • Seal all envelope seams, joints and penetrations
      • Insulate pipes, ducts and other cold surfaces
    architect
  • 20. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.16 Buildings with Attached Parking Garages. Reduce infiltration of vehicular exhaust
      • Maintain garage pressure below adjacent occupied space
      • Or, use a vestibule
      • Or, otherwise design to minimize air migration from garage to occupied space
    architect
  • 21. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.17 Air Classification and Recirculation. Reduce recirculation of “dirty” air to “cleaner” spaces
      • Designate air leaving each space or location ( see Table 6.1 )
        • Class 1: Low contaminant concentration (office)
        • Class 2: Mild concentration (dining room)
        • Class 3: Significant concentration (daycare sick room)
        • Class 4: Highly objectionable or potentially harmful concentration
      • Design to limit air recirculation as follows:
        • Class 1 to any space or location
        • Class 2 to self, other Class 2 or Class 3
        • Class 3 to self
        • Class 4 to outdoors only
  • 22. Std 62.1-2007 Section 5 Systems and Equipment
    • 5.18 Requirements for Buildings Containing ETS Areas and ETS-Free Areas. Reduce level of ETS in ETS-free areas
      • Classify each area as ETS or ETS-free
      • Pressurize ETS-free areas with respect to ETS areas
      • Separate ETS/ETS-free areas with walls, doors
      • Maintain transfer airflow paths
      • Don’t recirculate from ETS to ETS-free at air handler
      • Exhaust from ETS areas
      • Signage : “This area may contain ETS”
    architect 2007: Added Section 5.18: ETS/ETS-free separation requirements
  • 23. what does Std 62.1 require? Must Comply With …
    • General requirements (Sect 4 and 5)
      • To reduce generation of indoor contaminants and introduction of outdoor contaminants
    • Ventilation requirements (Sect 6)
      • To dilute and remove indoor contaminants
    • Construction, startup, operation and maintenance requirements (Sect 7 and 8)
      • To assure installation/operation as designed
  • 24. Std 62.1-2007 Section 6.0 Procedures
    • 6.1 General. For mechanically ventilated systems, find minimum OA intake using either the VRP or the IAQP
      • 6.1.1 Ventilation Rate Procedure (VRP). Prescribes procedures and outdoor air rates, assuming typical space contaminant sources and source strengths
      • 6.1.2 IAQ Procedure (IAQP). Requires analysis of contaminant sources, concentration targets and perceived air quality targets and calculation of outdoor air rates needed to assure IAQ-performance specified
    Compliance with Standard 62.1 using the IAQ procedure does NOT meet LEED NC EQp1
  • 25.
    • 6.2 Ventilation Rate Procedure. Prescribes zone outdoor air rates & system minimum intake calculation procedures
    • 6.2.1 Air Treatment. If outdoor air is judged to be unacceptable per Section 4.1 assessment:
      • Use MERV 6 filter in PM10 non-attainment regions
      • Use 40% efficient ozone filter in O 3 non-attainment regions with very high peak ozone (160 ppm or higher)
      • Document design assumptions in all non-attainment regions
    Std 62.1-2007 Section 6.2 Ventilation Rate Procedure Ozone filtration is required for LEED-NC projects in some regions of country
  • 26. non-attainment areas PM 10 (size ≤ 10 microns) US EPA AQS Database January 17, 2007 6.2.1 OA Treatment: Need MERV 6 filter
  • 27. non-attainment areas ( future ) PM 2.5 (size ≤ 2.5 microns) US EPA AQS Database January 17, 2007 Future: Addendum 62.1c would require MERV 11 in many locations
  • 28. non-attainment areas Ozone (8-hour) US EPA AQS Database January 17, 2007 6.2.1 OA Treatment: Need 40% air cleaner where 1-hour peak exceeds 160 ppb Fresno, Riverside, Long Beach
  • 29. non-attainment areas ( future ) Ozone (8-hour) US EPA AQS Database January 17, 2007 Future: Addendum 62.1c require 40% air cleaners in many more locations
  • 30. Std 62.1-2007 Section 6.2 VRP – Zone Calculaitons
    • 6.2.2 Zone Calculations. To assure prescribed breathing-zone dilution-ventilation with outdoor air:
      • Use Table 6.1 rates (both cfm/person and cfm/sf) to find breathing zone outdoor airflow : Vbz = Rp*Pz + Ra*Az
      • Use Table 6.2 defaults to find zone air distribution effectiveness , Ez (typically 1.0 in cooling, 0.8 in heating)
      • Use Equation 6-2 to find zone outdoor airflow for each zone: Voz = Vbz/Ez
  • 31. ventilation rate procedure Minimum Ventilation Rates
    • Table 6-1: Minimum breathing-zone rates for 63 categories
    Office 20 0.0 5.0 0.06 Classroom (ages 5-8) 15 0.0 10.0 0.12 Lecture classroom 15 0.0 7.5 0.06 Retail sales 0 0.3 7.5 0.12 Auditorium 15 0.0 5.0 0.06 Std 62-2001 Std 62.1-2007 Rp Ra Rp Ra Occupancy category cfm/p cfm/ft² cfm/p cfm/ft² Prescribes both per-person and per-area rates
  • 32. ventilation rate procedure Effective Minimum Rates Office (5p) 100 20.0 85 17.0 Classroom (ages 5-8) (25p) 375 15.0 370 15.0 Lecture classroom (65p) 975 15.0 550 8.5 Retail sales (20p) 300 15.0 270 14.0 Auditorium (150p) 2250 15.0 810 5.4 Occupancy category (default density/1000 ft²) Std 62-2001 Vbz cfm Effective cfm/p Std 62.1-2007 70% of OA rates drop; 30% stay same or rise Comparison of breathing-zone OA flow Vbz cfm Effective cfm/p
  • 33. ventilation rate procedure Effective Minimum Rates Daycare sickroom (25p) 10 0.18 430 17.2 Univ/Col laboratory (25p) 10 0.18 430 17.2 Central laundry rm (10p) 5 0.12 170 17.0 Res dwelling unit (5p) 5 0.06 85 17.0 Res corridor (--) 0 0.06 60 NA Occupancy category (default density/1000 ft²) Std 62.1-2007 Vbz cfm Effective cfm/p Check Standard for complete list of rates New rates and breathing-zone OA flow Rp cfm/p Ra cfm/ft 2 2007: Added some occupancy categories/rates, for example …
  • 34.
    • 6.2.3 Single-Zone Systems. To assure proper intake airflow for system with one air handler per zone:
      • Find system-level outdoor air intake flow : Vot = Voz
    • 6.2.4 100% Outdoor Air Systems. Assure proper intake airflow for system with one air handler supplying only outdoor air to many zones.
      • Find system-level outdoor air intake flow : Vot =  Voz
    Std 62.1-2007 Section 6.2 VRP – System Calculations
  • 35.
    • 6.2.5 Multiple-Zone Recirculating Systems. Intake airflow for system with one AHU supplying mixed air to many zones:
      • Find outdoor air intake flow (Vot) using prescribed equations and procedure to account for system ventilation efficiency (Ev): Vot = Vou/Ev … outdoor air intake flow Vou = D*  Rp*Pz +  Ra*Az … OA used in zones D = Ps/  Pz … population diversity factor Ev = min(Evz) … system ventilation efficiency
      • Evz = 1 + Xs – Zd … (Appendix A)
      • Xs = Vou/Vps … average OA fraction
      • Zd = Voz/Vdz … zone discharge OA fraction
    Std 62.1-2007 Section 6.2 VRP – System Calculations
  • 36.
    • 6.2.5 Multiple-Zone Recirculating Systems. Intake airflow for system with one AHU supplying mixed air to many zones:
      • Find outdoor air intake flow (Vot) using prescribed equations and procedure to account for system ventilation efficiency (Ev): Vot = Vou/Ev … outdoor air intake flow Vou = D*  Rp*Pz +  Ra*Az … OA used in zones D = Ps/  Pz … population diversity factor Ev = min(Evz) … system ventilation efficiency
      • Evz = 1 + Xs – Zd … (Appendix A)
      • Xs = Vou/Vps … average OA fraction
      • Zd = Voz/Vdz … zone discharge OA fraction
    Std 62.1-2007 Section 6.2 VRP – System Calculations Incidentally, Vdz = minimum expected discharge airflow … which might seem to conflict with Std 90.1 reheat airflow restrictions, but Exception a5 in Std 90.1 can help resolve it.
  • 37. Std 62.1-2007 Section 6.2 Ventilation System Example
    • Do we have time for an example?
      • No
      • But, I found total OA intake for a 6-zone school, using different systems and methods:
        • One RTU per zone (six single-zone systems), both in cooling and heating
        • One FC per zone, and a 100% OA system, with both CV and VAV ventilation airflow
        • A reheat VAV ( single-path multiple-zone ) system using both default Ev and calculated Ev
        • A series fan-powered VAV ( dual-path multiple-zone ) system using calculated Ev
  • 38. VRP 6-zone school example Zone-Level Calculations * Average (81% of 40 peak) Step 1: Vbz = Rp*Pz + Ra*Az Step 2: Look up Ez Step 3: Voz = Vbz/Ez 680 1.0 2,000 0.18 32* 10 North art classrm 85 1.0 1,000 0.06 5 5 Interior offices 2,190 1.0 4,000 0.06 260 7.5 East lecture class 2,190 1.0 4,000 0.06 260 7.5 North lecture class 1,880 1.0 4,000 0.12 140 10 West classrms (9+) 1,880 1.0 4,000 0.12 140 10 South classrms (9+) cfm -- ft 2 cfm/ft 2 people cfm/per Voz Ez Az Ra Pz Rp Example School
  • 39. VRP – system calculations Six Single-Zone Systems - Clg * Average (81% of 40 peak) Step 1: Vbz = Rp*Pz + Ra*Az Step 2: Look up Ez Step 3: Voz = Vbz/Ez Step 4: Vot = Voz each zone 8,900 Vot = Total zone OA flow 680 1.0 2,000 0.18 32* 10 North art classrm 85 1.0 1,000 0.06 5 5 Interior offices 2,190 1.0 4,000 0.06 260 7.5 East lecture class 2,190 1.0 4,000 0.06 260 7.5 North lecture class 1,880 1.0 4,000 0.12 140 10 West classrms (9+) 1,880 1.0 4,000 0.12 140 10 South classrms (9+) cfm -- ft 2 cfm/ft 2 people cfm/per Voz Ez Az Ra Pz Rp Example School
  • 40. VRP – system calculations 100% OA Systems – CV *Average (81% of 40) Step 4: Vot =  Voz Step 1: Vbz = Rp*Pz + Ra*Az Step 2: Look up Ez Step 3: Voz = Vbz/Ez 8,900 Vot = OA intake flow (Vot) 680 1.0 2,000 0.18 32* 10 North art classrm 85 1.0 1,000 0.06 5 5 Interior offices 2,190 1.0 4,000 0.06 260 7.5 East lecture class 2,190 1.0 4,000 0.06 260 7.5 North lecture class 1,880 1.0 4,000 0.12 140 10 West classrms (9+) 1,880 1.0 4,000 0.12 140 10 South classrms (9+) cfm -- ft 2 cfm/ft 2 people cfm/per Voz Ez Az Ra Pz Rp Example School
  • 41. VRP – system calculations 100% OA Systems – CV *Average (81% of 40) Note: Must assume peak (or average) population in every zone because ventilation airflow per zone is constant. 8,900 Vot = OA intake flow (Vot) 680 1.0 2,000 0.18 32* 10 North art classrm 85 1.0 1,000 0.06 5 5 Interior offices 2,190 1.0 4,000 0.06 260 7.5 East lecture class 2,190 1.0 4,000 0.06 260 7.5 North lecture class 1,880 1.0 4,000 0.12 140 10 West classrms (9+) 1,880 1.0 4,000 0.12 140 10 South classrms (9+) cfm -- ft 2 cfm/ft 2 people cfm/per Voz Ez Az Ra Pz Rp Example School
  • 42. multiple-zone system calculations Single-Path VAV: Calc Ev Step 4: Find outdoor air fraction for each zone: Zd = Voz/Vdzm = 1880/4000 = 0.47 * System population Ps = 550; Load diversity factor = 0.70 0.52 1,300 680 1,700 32* North art classrm 0.28 300 85 500 5 Interior offices 0.55 4,000 2,190 7,900 260 East lecture class 0.55 4,000 2,190 5,500 260 North lecture class 0.47 4,000 1,880 6,700 140 West classrms (9+) 0.47 4,000 1,880 6,500 140 South classrms (9+) (5,6,7) -- cfm cfm cfm people Evz Zd Vdzm Voz Vdz Pz Example School
  • 43. multiple-zone system calculations Single-Path VAV: Calc Ev Step 5a: Find occupant diversity: D = Ps/  Pz = 550/837 = 0.66 Step 5b: Find uncorrected outdoor air intake: Vou = D*  (Rp*Pz) +  (Ra*Az) = 0.66*7,000 + 1,900 = 6,500 cfm * System population Ps = 550; Load diversity factor = 0.70 6,500 Vou = Step 5 -- -- -- Uncorrected OA flow -- 0.52 1,300 680 1,700 32* North art classrm -- 0.28 300 85 500 5 Interior offices -- 0.55 4,000 2,190 7,900 260 East lecture class -- 0.55 4,000 2,190 5,500 260 North lecture class -- 0.47 4,000 1,880 6,700 140 West classrms (9+) -- 0.47 4,000 1,880 6,500 140 South classrms (9+) (5,6,7) -- cfm cfm cfm people Evz Zd Vdzm Voz Vdz Pz Example School
  • 44. multiple-zone system calculations Single-Path VAV: Calc Ev * Average (81% of 40 peak) Step 6a: Find system primary airflow: Vps = LDF*  Vpz = 0.70*28,800 = 20,200 Step 6b: Find average outdoor air fraction: Xs = Vou/Vps = 6,500/20,200 = 0.32 Step 6c: Find ventilation efficiency for each zone: Evz1 = 1+Xs–Zd = 1+0.32–0.47 = 0.85 Step 6d: Find system ventilation efficiency Ev = min(Evz) = 0.77 0.77 Ev = -- -- -- Sys vent eff 0.32 Xs = Step 6 Uncorrected OA frac 6,500 Vou = Step 5 -- -- -- Uncorrected OA flow 0.80 0.52 1,300 680 1,700 32* North art classrm 1.04 0.28 300 85 500 5 Interior offices 0.77 0.55 4,000 2,190 7,900 260 East lecture class 0.77 0.55 4,000 2,190 5,500 260 North lecture class 0.85 0.47 4,000 1,880 6,700 140 West classrms (9+) 0.85 0.47 4,000 1,880 6,500 140 South classrms (9+) (5,6,7) -- cfm cfm cfm people Evz Zd Vdzm Voz Vdz Pz Example School
  • 45. multiple-zone system calculations Single-Path VAV: Calc Ev Step 7: Find outdoor air intake flow: Vot = Vou/Ev = 6,500/0.77 = 8,400 * System population Ps = 550; Load diversity factor = 0.70 0.32 Xs = Step 6 Uncorrected OA frac 0.77 Ev = -- -- -- Sys vent eff 8,400 Vot = Step 7 -- -- -- Outdoor air intake 6,500 Vou = Step 5 -- -- -- Uncorrected OA flow 0.80 0.52 1,300 680 1,700 32* North art classrm 1.04 0.28 300 85 500 5 Interior offices 0.77 0.55 4,000 2,190 7,900 260 East lecture class 0.77 0.55 4,000 2,190 5,500 260 North lecture class 0.85 0.47 4,000 1,880 6,700 140 West classrms (9+) 0.85 0.47 4,000 1,880 6,500 140 South classrms (9+) (5,6,7) -- cfm cfm cfm people Evz Zd Vdzm Voz Vdz Pz Example School
  • 46. VRP 6-zone school example OA Intake Flow Summary No population diversity credit Penalty for “too warm” htg air No population diversity credit No population diversity credit Conservatively low default Ev value Equations for more accurate Ev Two ventilation paths, highest Ev 10,800 VAV Default Ev 7,800 Series FP VAV 8,900 100% OA – VAV 8,400 VAV Calculated Ev 8,900 100% OA – CV 11,100 Single-Zone Htg 8,900 Single-Zone Clg OA Intake Vot Ventilation System
  • 47. VRP 6-zone school example OA Intake Flow Summary 7,800 8,400 10,800 8,900 8,900 11,100 8,900 OA Intake (2007 Vot) 10,900 10,900 10,900 12,600 12,600 15,800 12,600 OA Intake (2001 Vot) -1 MZS-VAV Default Ev -28 MZS-VAV Series FP -29 100% OA – VAV -23 MZS-VAV Calc Ev -29 100% OA – CV -30 Single-Zone Htg -29 Single-Zone Clg % Chg Ventilation System
  • 48.
    • 6.2.6 Design for Varying Operating Conditions.
      • 6.2.6.1 Variable Load Conditions . Design to provide the required OA flow whenever occupied and at all loads
      • 6.2.6.2 Short-Term Conditions. If peak population duration is “short” or if intake flow varies, designer may (optional) base design calculations on average population over time T (three zone time constants) T = 3*volume / Vbz-peak
    Std 62.1-2007 Section 6.2 Ventilation Rate Procedure This approach replaces the “intermittent occupancy” approach in Std 62-2001.
  • 49.
    • 6.2.7 Dynamic Reset. To assure outdoor airflow meets requirement for ventilation load, without over-ventilating:
      • Ma y (optional) reset zone minimum OA flow based on variations in occupancy (DCV)
      • Ma y (optional) reset OA intake flow based on variations in efficiency (ventilation reset control)
      • Ma y (optional) reset VAV zone minimum airflow based on variations in actual intake airflow (economizer)
    Std 62.1-2007 Section 6.2 Ventilation Rate Procedure This Section includes operating control options, not minimum design requirements.
  • 50. operation for varying conditions Zone-Level DCV Approaches
      • TOD: Determine Voz using effective population, Pz’ , based on t ime- o f- d ay schedule
      • OCC: Determine Voz using Pz’ equal to design or zero population, based on occ upancy sensors
      • CNT: Determine Voz using Pz’ equal to actual population, based on direct c ou nt
    Voz = (Rp* Pz’ + Ra*Az)/Ez (Cr – Co) = k*m*Pz/Vbz = 8400*1.25*Pz/Vbz = 10,500*Pz/Vbz
      • CO 2 : Use differential CO 2 to maintain current Vbz = > Vbz-req for current population, based on:
  • 51. zone-level CO 2 -based DCV (Users Manual) Modulate Vbz   CO 2 10 20 200 400 600 800 1000 zone population, Pz breathing zone OA, Vbz 30 40 50 60 differential CO 2 , ppm 200 400 600 800 1000 1200 0 0 0 1200 First, find max and min values for  CO 2 Vbz-min = 60 cfm  C-min = 0 ppm Vbz-des = 548 cfm  C-max = k*m*Pz/Vbz = 10,500*65/548 = 1240 ppm Vbz = 7.5 × Pz + 0.060 × Az
  • 52. zone-level CO2-based DCV (Users Manual) Modulate Vbz   CO 2  C (CO 2 , ppm) Vbz (cfm) 60 548 0 1240 Vbz = 0.393 ×  C + 60 The Controller Second, define the proportional Controller
  • 53. zone-level CO 2 -based DCV (Users Manual) Modulate Vbz   CO 2 10 20 200 400 600 800 1000 zone population, Pz breathing zone OA, Vbz 30 40 50 60 differential CO 2 , ppm 200 400 600 800 1000 1200 0 0 0 1200 Controller adjusts Vbz in direct proportion to sensed  CO 2 Optional CO 2 DCV can save operating energy For single zone systems, Vbz => min Vbz req’d To analyze Controller operation: … 1. Assume initial  C-int, find: Vbz = 0.393*  C-int + 60 2. Given Pz and Vbz, find:  C = Pz*k*m/Vbz 3. Repeat until  C-int =  C
  • 54.
    • 6.2.7 Dynamic Reset. To assure outdoor airflow meets requirement for ventilation load, without over-ventilating:
      • Ma y (optional) reset zone minimum OA flow based on variations in occupancy (DCV)
      • Ma y (optional) reset OA intake flow based on variations in efficiency (ventilation reset control)
      • Ma y (optional) reset VAV zone minimum airflow based on variations in actual intake airflow (economizer)
    Std 62.1-2007 Section 6.2 Ventilation Rate Procedure This Section includes operating control options, not minimum design requirements.
  • 55. Ventilation Reset Control
    • Varies OA intake by accounting for current system-ventilation efficiency based on:
      • Current ventilation zone requirements Vbz = (an entry) Voz = Vbz/Ez (calculated) Vdz = (from flow sensor)
      • Current ventilation fraction for each zone Zd = Voz/Vdz
      • Intake airflow (Vot) calculated using actual parameters and the multiple-space equations
  • 56. VAV ventilation reset control (no DCV) Single-Duct VAV System 100% system load (20,200 cfm) VRC only: low D, constant Vou, reduces Vot 8, 810 © 2005 American Standard Inc. Vot w/vent reset disc airflow Vdz 4,000 4,100 4,200 4,300 300 1,300 vent rate Voz 1,880 1,880 2,190 2,190 85 680 vent fraction Zdz 0.470 0.459 0.521 0. 509 0.283 0.585 Vou = 6,500 Xs = Vou/Vps = 6,500/18,200 = 0.357 Ev = 1 + 0.357 – 0.585 = 0.772 Vot = Vou/Ev = 6,500/0.772 = 8,410 90% system load (18,200 cfm) 8,810 Vot req’d @ design 8,810 8,410 disc airflow Vdz 5,000 5,400 4,000 4,000 500 1,300 vent rate Voz 1,880 1,880 2,190 2,190 85 760 vent fraction Zdz 0.376 0.351 0.548 0.548 0.170 0.585 Vou = D*  Rp*Pz +  Ra*Az = 0.65 *7,130 + 1860 = 6,500 Xs = Vou/Vps = 6,500/20,200 = 0.322 Ev = 1 + 0.322 – 0.585 = 0.738 Vot = Vou/Ev = 6,500/0.738 = 8,810
  • 57. OA RA SA central station air handler with controls communicating BAS
    • Reset outdoor airflow (TRAQ™ damper)
    For Vent Reset: DDC/VAV, a BAS, OA flow sensor DDC/VAV terminals
    • Req’d ventilation (Vbz, Voz)
    • Actual discharge flow (Vdz)
    • Current ventilation fraction (Zd = Voz/Vpz)
    • Totals (Vou, Vps)
    • “ Used” OA fraction (Xs)
    • Sys vent efficiency (Ev)
    • New OA setpoint (Vot)
    VAV ventilation reset Single-Duct VAV System © 2005 American Standard Inc.
  • 58. VAV ventilation reset control (with DCV zones) Single-Duct VAV System disc airflow Vdz 5,000 5,400 4,000 4,000 500 1,300 vent rate Voz 1,880 1,880 2,190 2,190 85 760 vent fraction Zdz 0.376 0.351 0.548 0.548 0.170 0.585 Vou = D*  Rp*Pz +  Ra*Az = 0.65*7,130 + 1860 = 6,500 Xs = Vou/Vps = 6,500/20,200 = 0.332 Ev = 1 + 0.332 – 0.585 = 0.738 Vot = Vou/Ev = 6,500/0.738 = 8,810 100% VRC w/zone-level DCV reduces Vot even more © 2005 American Standard Inc. 8,810 Vot w/vent & DCV 8,810 8,410 5 7,040 Vot w/vent reset Pz disc airflow Vdz 4,000 4,100 4,200 4,300 300 1,300 vent rate Voz 1,880 1,880 2,190 2,190 85 680 vent fraction Zdz 0.470 0.459 0.146 0. 509 0.283 0.431 360 0.277 915 0.218 Sense CO 2 , find new Voz Sense motion Vou = D*(  NON Rp*Pz-des) +  NON (Ra*Az) +  DCV-NON-CO2 (Rp*Pz-est + Ra*Az) +  CO2 (Vbz-est) = 0.65*(4,780) + 1260 + 0 + 360 + 915 = 5,640 Xs = Vou/Vps = 5,640/18,200 = 0.310 Ev = 1 + 0.310 – 0.509 = 0.801 Vot = Vou/Ev = 5,640/0.801 = 7,040 CO 2 OCC 260 140 140 260 40 90% 260 140 140 ?? 5 0 Pz’
  • 59. Std 62.1-2007 Section 6.2 VRP – DCV and VRC in MZS
    • In operation we could:
      • Sense CO2 or estimate Pz in one or more zones (DCV) and determine currently required breathing zone OA (Vbz)
      • Use current Vbz for DCV zones and solve the MZS equations to find current set point for OA intake (Vot)
      • Actual OA delivered all zones would always equal or exceed minimum required OA flow (Vbz)
    • Does this approach work?
      • Yes, but I don’t know how well … it must be analyzed, a TC 1.4 RTAR is in the works
    Future: Working on Addendum 62.1g to strengthen optional DCV requirements
  • 60.
    • 6.2.8 Exhaust Ventilation. To assure minimum removal of local contaminants:
      • Exhaust some zones at rates prescribed in Table 6.4. Examples of more than 20 zones listed:
        • Art classroom 0.70 cfm/ft2
        • Beauty and nail salons 0.60
        • Kitchenettes 0.30
        • Locker/dressing rooms 0.25
        • Copy, printing rooms 0.50
        • Toilet – public 50 (cont.) or 70 (cyc.) cfm/wtr closet
    Std 62.1-2007 Section 6.2 Ventilation Rate Procedure 2007: Added a few, e.g., residential kitchen exhaust
  • 61.
    • 6.2.9 Ventilation for Smokin g Areas. To assure more-than-minimum ventilation for smoking-permitted areas, even though specific rates on are not prescribed:
      • Provide more ventilation and/or air cleaning than prescribed in Table 6.1 in zones where smoking is allowed
      • Design to prevent air transfer from smoking-permitted to no-smoking areas (thru doors and openings, for example)
      • Design to prevent air recirculation from smoking-permitted to no-smoking areas (thru the air handler)
    Std 62.1-2007 Section 6.2 Ventilation Rate Procedure Future: These requirements will be altered by Addendum 62.1i
  • 62.
    • 6.3.1.1 Contaminant Sources. Must identify contaminants of concern, along with sources and source strengths
    • 6.3.1.2 Contaminant Concentration. Must specify target concentration and exposure time, referencing cognizant authority , for each C of C
    • 6.3.1.3 Perceived IAQ. Must specify target perceived air quality in terms of percent satisfied
    • 6.3.1.4 Design Approaches. Must follow an acceptable design procedure to find required zone and system airflow rates , and other parameters (e.g., air cleaner efficiency )
    Std 62.1-2007 Section 6.3 IAQ Procedure
  • 63.
    • May be used in lieu of VRP:
      • To take ventilation-credit for low-emitting materials
      • To take ventilation-credit for air cleaning
      • To achieve specific target contaminant concentrations or levels of perceived IAQ (percent satisfied)
      • But …
        • It doesn’t apply when C of C is ETS … there’s no target concentration from any cognizant authority to reference
        • It doesn’t apply to LEED-NC jobs. EQ prerequisite 1 requires compliance with the VRP of Std 62.1-2004
        • It’s not allowed directly by the model codes
    Std 62.1-2007 Section 6.3 IAQ Procedure Future: Needs attention
  • 64. what does Std 62.1 require? Must Comply With …
    • General requirements (Sect 4 and 5)
      • To reduce generation of indoor contaminants and introduction of outdoor contaminants
    • Ventilation requirements (Sect 6)
      • To dilute and remove indoor contaminants
    • Construction, startup, operation and maintenance requirements (Sect 7 and 8)
      • To assure installation/operation as designed
  • 65. Std 62.1-2007 Section 7 Construction/System Start-Up
    • 7.1 Construction Phase. Reduce IAQ problems introduced during construction. For example:
      • 7.1.2. Install unit filters before operating fans
      • 7.1.3. Protect materials from rain and moisture. Don’t install materials with visible microbial growth
      • 7.1.4. Reduce transfer of construction contaminants into occupied areas
      • 7.1.5. Construct ducts per SMACNA standards
  • 66. Std 62.1-2007 Section 7 Construction/System Start-Up
    • 7.2 System Start-Up. Reduce potential for IAQ problems prior to occupancy. For example:
      • Balance air flows to assure delivery of at least minimum outdoor air intake flow and zone outdoor airflow per Section 6
      • Test drain pans for proper drainage (or get certification)
      • Clean air distribution system prior to start up
      • Test OA dampers for proper operation
      • Provide ventilation system documentation (O&M Manual, HVAC controls information, air balance report, construction drawings, design criteria and assumptions) to owner or owner agent
  • 67. operating requirements 8.0 Operation & Maintenance
    • 8.2 Operations and Maintenance Manual. Develop a building operations and maintenance manual
    • 8.3 Ventilation System Operation. Operate in accordance with Manual
    • 8.4 Ventilation System Maintenance. Maintain in accordance with Manual
    Building Operation Manual Future: Working on Addendum related to Std 180
  • 68. 62.1 Update Summary
    • SSPC 62.1 continues to refine Std 62.1 in response to:
      • Change proposals (both internal and external)
      • Interpretation requests
      • Changes within the industry (LEED, building code needs)
    • Continuous maintenance in action!
  • 69. In Summary (LEED-NC)
    • To qualify for 62.1-related LEED-NC credits
      • EQp1 : Comply with Section 4-7. Use VRP (not IAQP)
      • EAc1: Reduce operating energy compared to baseline ( dynamic reset approaches can help)
      • EQc1: Monitor CO2 and/or OA intake flow
      • EQc2: Increase OA intake flow by 30% over VRP , or design Natural Vent systems per CIBSE 237
      • EQ3.1: During construction, meet SMACNA IAQ Guidelines, protect materials from moisture, use temporary MERV 8 filters at return grilles (if fans operate)
      • EQ5: Use entryway systems, local exhaust, and MERV 13 filters in each supply air path
  • 70. What about those Questions on the 2008 Member Ballot?
    • They relate directly to Std 62.1 and other “IAQ” or ventilation standards
    • “ Dude, check it out. For me they’re just a’ight.”
      • But, I voted YES to all, because they tend to clarify provisions in the Member Petition of 1999
      • For example (if we have time) …
  • 71. Membership Petition (1999)
    • 1. The standard shall specify control of only those contaminants for which a nationally recognized authority has established a maximum permissible concentration and for which standardized test procedures have been established.
      • Does this mean the Standard MUST specify control for some contaminants? Or, does it prohibit the specification of some limits?
      • Does it mean that ASHRAE can set ITS OWN limits for some contaminants?
  • 72. Ballot Question 1
    • Should ASHRAE Standards … contain health-based limits for pollutant concentrations only when those limits have previously been issued by nationally or internationally recognized health authorities, e.g. U.S. EPA, OSHA or WHO, and for which standardized measurement methods exist?
    • To me, YES means that for ASHRAE standards, I recommend:
      • Use of health-based limits only for contaminants with established limits and measurement methods, and if the limits are set by health authorities ( ASHRAE can’t set health-related limits )
      • For example, a standard can include a limit for ozone, but not for ETS
  • 73. Ballot Question 2
    • Should ASHRAE Standards and Guidelines be allowed to specify means and methods for limiting the concentrations of pollutants normally considered in the design of HVAC systems, even for pollutants that may not have maximum permissible concentration levels set by a recognized health authority or for which standard measurement methods don’t exist?
    • To me, YES means that for ASHRAE standards, I recommend:
      • Allowing methods for limiting contaminants without health-based limits (e.g., fans for toilet exhaust) ( ASHRAE can set non-health related contaminant limits )
      • [For example, a CO 2 limit (well below health limits) could be selected and used to control OA flow]
  • 74. Membership Petition (1999)
    • 2. The standard shall specify concentration limits and conditions only for contaminants that can be measured using standardized test equipment and procedures in accordance with ASHRAE Standard 111 (or its successor) and using equipment normally available in the HVAC&R industry to test and balance technicians. (Temperature, Humidity, and CO2 are some measurable examples.)
      • Does this mean the Standard MUST specify “limits and conditions” for some contaminants?
      • Or, does it PROHIBIT the specification of “limits and conditions” for some contaminants?
  • 75. Ballot Question 3
    • Should ASHRAE Standards … be precluded from requiring measurement of contaminant … or specifying concentration limits that cannot be measured using equipment and procedures in ASHRAE Standard 111 … or using equipment that is common in building ventilation assessment?
    • To me, YES means that for ASHRAE standards, I recommend:
      • No requirements for measurement of or specific limits for concentrations if they can’t be measured using readily accessible measurement equipment ( ASHRAE can’t require measurement of hard-to-measure concentrations )
      • [I almost voted NO, since the IAQP requires target limits that would be hard to measure, but I voted YES because such limits are for design, and need not be sensed for operation]
  • 76. Membership Petition (1999)
    • 3. The standard shall not require compliance by application of complex algorithms that contain factors such as mixing efficiencies, air change effectiveness, etc., unless they can be measured and verified by field test using standard equipment as described in ASHRAE Standard 111 (or its successor) and are normally available to test and balance technicians.
      • Does it make sense to prohibit certain “complex algorithms ” (those that contain design parameters that can’t be measured using normally available means)?
      • Does it make engineering-sense to eliminate design calculation methods just because they require factors that can’t be easily measured during operation ?
  • 77. Ballot Question 5
    • Should ASHRAE Standards … be permitted to contain factors for use in design calculation , such as mixing efficiencies and air change effectiveness, as long as it is the consensus of the standards writing body that these factors are important to providing acceptable indoor air quality?
    • To me, YES means that for ASHRAE standards, I recommend:
      • That design factors which are important for providing acceptable IAQ be permitted in design calculations, even if they can’t be readily measured in the field ( ASHRAE calculations can include hard-to-measure design parameters, if measurement isn’t required )
      • [Such design factors can be presented as default values, and need not be measured or sensed for operational control]
  • 78. Membership Petition (1999)
    • 4. The goal of the standard shall be to provide general dilution ventilation of occupied spaces. The standard shall not make claim for health, comfort, or occupant acceptability.
      • “General dilution ventilation” to what end ? Odor-comfort, good visibility, occupant health? Shouldn’t the goal include the answer to “why ventilate?”
      • What does it mean to “make claim for health, comfort, or occupant acceptability?”
  • 79. Ballot Question 4
    • Should ASHRAE Standards and Guidelines strive to provide health, comfort and/or occupant acceptability consistent with ASHRAE policy?
    • To me, YES means that for ASHRAE standards, I recommend:
      • That ventilation-related goals reflect ASHRAE policy , which indicates that standards meant to protect public health and safety , and to provide occupant comfort and environmental acceptability are appropriate ( ASHRAE can write standards with health, comfort and acceptability goals )
      • [Setting better health, comfort and acceptability as a goal neither claims nor guarantees that such improvements will actually result from compliance – life is complicated]
  • 80. Questions? ASHRAE 62.1 update: Where are we now?