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ASHRAE Std Ventilation for Acceptable Indoor Air Quality ASHRAE 62

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Presentation on theme: "ASHRAE Std Ventilation for Acceptable Indoor Air Quality ASHRAE 62"— Presentation transcript:

1 ASHRAE Std Ventilation for Acceptable Indoor Air Quality ASHRAE 62.1 update: Overview - Where are we now? This presentation is the companion to a presentation titled ASHRAE 62.1 Update – Ventilation Rate Procedure and IAQ Procedure. This presentation explains the requirements of ASHRAE Standard but does not explain the calculation requirements. Ideally, this presentation precedes the calculation presentation. Please be aware that there is more to complying with standard 62 than just the calculation of ventilation rates. Acceptable Indoor air quality requires more than ventilation.

2 ASHRAE Std 62 update An Outline
General comments General requirements Ventilation requirements Construction and O/M requirements Questions Today’s presentation is going to focus on the history and recent updates of Standard 62.1,Ventilation for Acceptable Indoor Air Quality. We’ll discuss the key changes that have occurred and their impact on ventilation design. We will also explain the continuous maintenance process that this standard operates under, and the processes by which the user can request standard interpretations and submit change proposals.

3 ASHRAE Standard 62 What’s Its History?
Prescriptive Commissioning O&M Combustion air Filtration IAQ-Health disclaimers Smoking disclaimers Clarified CO2as ventilation metric Alternative Air Quality Proc. Updated 1970 1980 1990 2000 2010 History of changes is documented in Forewords of previous Standard versions. Some changes are shown here. Key recent changes include split off of residential standard (62.2), leaving 62.1 to cover commercial and high rise residential buildings. Environmental tobacco smoke, although discussed as an important factor since 1981, was addressed in 2004 by explicitly removing prescribed minimum outdoor airflow rates for zones with ETS. Outside air rates are now specified on a per-area and a per- occupant basis. Removed Thermal Comfort Ventilation Rate Proc. IAQ Proc. Commercial and High Rise Res. Enforceable code language ETS vent. rates not covered Vent. Rate. Proc. Modified Occupant and area vent. rates first issued

4 ASHRAE Standard 62.1-2007 & Related Activities…
Std is the most current version IMC adopted methodology and rates in 2007 Supplement Several educational courses are available from ASHRAE The current version of ASHRAE 62.1 is It is written in code adoptable language and is an ANSI consensus standard. The ventilation rate calculations and basic rates in the current International Mechanical Code and Uniform Mechanical Code are from ASHRAE ASHRAE provides several educational courses. Course information is available on the ASHRAE website.

5 Purpose 1.1 Specify minimum ventilation rates and other measures intended to provide IAQ that is acceptable to human occupants and that minimizes adverse health effects. 1.2 Intended for regulatory application to new buildings, and additions 1.3 Guide the improvement of IAQ in existing buildings. Note: Purpose text shortened to highlight key points. Read this text.

6 62.1-2007 Scope 2.1 All spaces intended for human occupancy.
2.2 Defines requirements for ventilation, air-cleaning design, commissioning, installation and O&M 2.3 Additional requirements and other standards may apply (labs, healthcare, industrial, etc.) 2.4 May be applied to both new and existing buildings, not intended to be used retroactively 2.5 Does not prescribe specific ventilation rates for smoking spaces Scope text shortened to highlight key points. Recommend that audience read actual text. Also: 62.2 covers single-family housing and multi-family structures of three stories of fewer does not cover vehicles and aircraft

7 Scope Con’t 2.6 Ventilation requirements based on chemical, physical, & biological contaminants 2.7 Consideration or control of thermal comfort is not included 2.8 Contains requirements, in addition to ventilation related to certain sources Read these requirements. After 2.9 It must be noted that this is a minimum ventilation standard for acceptable IAD. However, if one meets the requirements of standard 62.1, you will be effectively addressing the issues that typically cause IAQ concerns.

8 Scope Con’t 2.9 Acceptable IAQ may not be reached in all buildings meeting these requirements because of special conditions noted Definition Acceptable Indoor Air Quality: air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority (80% or more) of the people exposed do not express dissatisfaction It must be noted that this is a minimum ventilation standard for acceptable IAQ. However, if one meets the requirements of standard 62.1, you will be effectively addressing the issues that typically cause IAQ concerns.

9 General Requirements 4.0 Outdoor Air Quality
4.1 Regional Air Quality Must determine NAAQS attainment status If nonattainment, air cleaning is required in some cases 4.2 Local Air Quality Conduct observational site survey to identify local sources of air contaminants Determine the attainment status in your region. If the area is nonattainment for ozone or particulate matter, then air cleaning may be required by section Determine acceptability of outdoor air quality (site observation). Additionally ambient air quality monitoring is not required. The Users Manual provides examples.

10 General Requirements 4.0 Outdoor Air Quality
4.3 Documentation Regional air quality compliance status Local survey information Conclusions regarding acceptability of outdoor air quality Documentation of the outdoor air quality survey results and conclusions are required. Further actions such as modification of building orientation or additional filtration may be warranted, however they are not required by the standard. If you choose additional actions, you must document them ( ).

11 General Requirements 5.0 Systems and Equipment
5.1 Natural Ventilation. Must meet minimum requirements for location and size of openings 5.2 Ventilation Air Distribution. Must provide means to adjust (balance) Must be sure that mixing occurs in RA/OA mixing plenums 62.1 does accommodate the use of natural ventilation…for natural ventilation the openings must be permanent and readily accessible to the occupants… 5.2 refers to mechanical system ventilation…

12 General Requirements 5.0 Systems and Equipment
5.3 Exhaust Duct Location. Operate exhaust ducts (with harmful contaminants) at negative pressure 5.4 Ventilation System Controls. Control to assure proper ventilation under any operating condition 5.5 Airstream Surfaces. Use materials that have documented resistance to microbial growth and erosion 5.3 Must exhaust harmful contaminants in negative pressure ducts to prevent leakage into occupied spaces, plenums 5.4 Must have controls to enable fan Noted: VAV systems with fixed dampers must comply (high % open). Leads to modulating damper and sensed OA flow 5.5 Must be documented through standard performance testing (UL, ASTM, etc.)

13 General Requirements 5.0 Systems and Equipment
5.6 Outdoor Air Intakes. Separate OA intake from outdoor contaminant sources Must comply with default minimum separation distances in Table 5-1. Examples: Loading dock 25 ft Dumpster 15 ft Surface below intake ft Cooling tower exhaust 25 ft Must limit rain water penetration (using hood, proper velocity, etc.) or manage water that penetrates Must use bird screens and prevent bird nesting This section is intended to minimize unintentional introduction of contaminants in the outdoor air. If a site survey identifies a pollution source on one side of the building, then that information would be used to locate the intakes to minimize bringing in contaminants from that source.

14 General Requirements 5.0 Systems and Equipment
5.7 Local Capture of Contaminants. Discharge air from non-combustion equipment with exhaust vents must be exhausted to outdoors 5.8 Combustion Air. Provide combustion air and exhaust air for indoor fuel-fired appliances Products of combustion from vented appliances shall be vented directly outdoors. It is preferred to capture or control contaminants at the source to prevent the release of potentially harmful materials into the occupied space….

15 General Requirements 5.0 Systems and Equipment
5.9 Particulate Matter Removal. Use a filter with a MERV 6 (or greater) upstream of dehumidifying coils and other wet-surface devices in supply stream Minimum efficiency recording value (MERV) refers to a filter tested and evaluated in accordance with ASHRAE Standard 52.2 procedures….”Note to speaker that the MERV may not be applicable to certain International requirements”

16 General Requirements 5.0 Systems and Equipment
5.10 Dehumidification Systems. Must limit indoor RH to 65% or less at design dew point condition Exception to RH limit: where occupancy requirements or processes dictate higher RH conditions. Intake airflow must be greater than relief/exhaust during cooling (to minimize moist air infiltration) Almost every air conditioning system dehumidifies at some condition. The dehumidification design conditions are not the peak design conditions. Then the details are specified in the standard. Basic constant volume (CV) systems may not comply with this requirement. CV systems that include controls to sense and limit RH can comply. Most VAV systems comply without RH sensing

17 General Requirements 5.10 Dehumidification Systems
At 75F, 65% rh gives a 13F “safety margin” before condensation 65% RH limit 62°F DP The 65% RH limit was selected (rather than a dew point limit) to reduce likelihood of high RH or condensation at surfaces within the space, to reduce likelihood of microbial growth.

18 General Requirements 5.0 Systems and Equipment
5.11 Drain Pans. Assure drainage without flooding or carryover Slope: 1/8” per foot toward outlet Drain: At lowest point, large enough to prevent overflow Drain seal: P-trap or other seal for negatively pressurized drain pans to prevent ingestion of air while allowing complete drainage (fan on or off) Pan size: length at least 1/2 coil height or as necessary to limit carryover Drain pans must drain

19 General Requirements 5.0 Systems and Equipment
5.12 Finned Tube Coils and Heat Exchangers Use drain pan Select to limit coil pressure drop to fpm face velocity If higher pressure drop, provide access on both sides for maintenance

20 General Requirements 5.0 Systems and Equipment
5.13 Humidifiers and Water Spray Systems Use potable water (or better) No downstream devices within absorption distance 5.14 Access for Inspection, Cleaning and Maintenance. 5.14 Provide adequate access to components listed in standard

21 General Requirements 5.0 Systems and Equipment
5.15 Building Envelope and Interior Surfaces Weather barrier to prevent water penetration into envelope Vapor retarder or other means to prevent condensation on cold surfaces within envelope Seal all seams, joints, penetrations to limit infiltration Insulate pipes, ducts expected to have surface temperature below surrounding dew point Although these envelope details are usually not under the HVAC designers purview, they are important considerations to reduce the potential for microbial growth, especially within the wall structure….

22 General Requirements 5.0 Systems and Equipment
5.16 Buildings with Attached Parking Garages. Limit infiltration of vehicular exhaust Maintain garage pressure at or below adjacent occupied space Or, use a vestibule Or, otherwise design to minimize air migration from garage to occupied space

23 General Requirements 5.0 Systems and Equipment
5.17 Air Classification and Recirculation. Limit recirculation or transfer of “dirty” air to “cleaner” spaces Classification - Designate air leaving each space using Table 6.1 Class 1: Low contaminant concentration (office) Class 2: Moderate concentration (dining room) Class 3: Significant concentration (sick room) Class 4: Highly objectionable or potentially harmful concentration Note that these classes of air relate to commercial applications for the Standard and that other industry Standards (ACGIH, etc.) have developed classes of air for non-commercial applications…

24 General Requirements 5.0 Systems and Equipment
Classification Manage recirculation as follows Class 1 to anywhere Class 2 to self, similar Class 2 or Class 3 or Class 4 Class 3 to self Class 4 to outdoors

25 General Requirements 5.0 Systems and Equipment
Re-designation of air class Air Cleaning. May reclassify air cleaned by passing it through an appropriate air-cleaning system Transfer. Mixed classes are re-designated. Energy Recovery. Energy recovery from class 2 (exhaust) airstreams must have no more than 10% leakage into a class 1 airstream. Reclassification of air by air cleaning requires approval of authority having jurisdiction. Class 3 air may be re-designated to Class1 in the process of energy recovery if diluted with OA so no more than 5% is Class 3 Transfer Example: Air mixed from Class 2 space and Class 1 space air streams must be designated Class 2

26 General Requirements 5.0 Systems and Equipment
5.18 Requirements when building has both ETS and ETS-Free areas. Does not purport to achieve acceptable IAQ in ETS areas. Spaces must be classified as ETS or ETS-Free Air must be kept separate by means of walls, automatic door closers and pressurization Pressurization. Relative pressure in ETS and ETS-Free areas may be demonstrated by various methods (Example - Engineering analysis, measurement, airflow measurement). Separation techniques between dwelling units and adjacent properties are thoroughly described in the Exceptions to Separation include other engineered solutions to maintain airflow to protect against movement of ETS laden air into ETS-Free areas - examples are described in

27 General Requirements 5.0 Systems and Equipment
5.18 (continued) Recirculation or transfer from ETS to ETS-Free is prohibited ETS areas must be exhausted to the outdoors The scope of the standard excludes setting specific ventilation rates for smoking areas. The current requirement is that smoking areas shall have more ventilation and/or air cleaning than comparable no smoking areas (6.2.9). This section addresses separation of ETS and ETS-free areas, not outdoor airflow rates or air cleaning requirements.

28 Ventilation Requirements 6.0 Procedures
6.1 General. Ventilation Rate Procedure or IAQ Procedure for outdoor airflow values for mechanical ventilation systems 6.1.1 Ventilation Rate Procedure. Prescribes rates & procedures based on typical space contaminant sources & source strengths This slide shows that there are two different procedures that can be used to design ventilation system for a building in the case of mechanical ventilation systems. These are a) Ventilation Rate Procedure and b) IAQ procedure. VRP is a prescriptive procedure that specifies minimum outdoor airflow rates which are based on contaminant sources and strengths that are typical for the listed space. The rates are meant to dilute and exhaust odorous bioeffluents from occupants and odorous and sensory irritant contaminants from other sources typical of that space type. Details of the ventilation calculations are covered in another presentation.

29 Ventilation Requirements 6.0 Procedures
6.1.2 IAQ Procedure. Requires calculation of rates based on analysis of contaminant sources, concentration targets and perceived air quality targets. The IAQ procedure is a performance-based design procedure in which calculations of outdoor airflow rates are based on analysis of contaminant sources, target concentrations and perceived air quality targets. The IAQ procedure allows designers to take credit for source-control and removal measures, such as low emission materials and gas-phase air cleaning devices.

30 Construction Requirements 7.0 Construction/Start-Up
7.1 Construction Phase Don’t operate air handlers without filters Protect building materials Protect occupied areas Limit migration of construction contamination into occupied space Speaker should stress don’t operate systems without proper filters and if system is operated before construction equipment to be protected with filtration and filters change often. Also refer audience to new SMACNA/ANSI Guideline “IAQ Guidelines for Occupied Buildings Under Construction” 2007 Edition.

31 Construction Requirements 7.0 Construction/Start-Up
7.1.5 Air Duct Construction shall be in accordance with the SMACNA duct construction standards and NFPA standards governing installation of HVAC systems 7.2 System Start-Up. Balance airflow values, test drain pans, clean up before starting, test damper controls

32 Construction Requirements 7.0 Construction/Start-Up
7.2.6 Documents including balance report, construction drawings and design criteria with assumptions shall be provided to Owner The Owner may be the operator or designee of the Owner….

33 Operating Requirements 8.0 Operation & Maintenance
8.2 Operations and Maintenance Manual. Develop and maintain a building operations and maintenance manual which shall include a maintenance schedule with frequencies of tasks. Building Operation Manual

34 Operating Requirements 8.0 Operation & Maintenance
8.3 Ventilation System Operation. Operate in accordance with Building Operations Manual 8.4 Ventilation System Maintenance. Maintain in accordance with Building Operations Manual. Proper maintenance of system is very important. Maintain design air flow at all times.

35 Operating Requirements 8.0 Operation & Maintenance
Coil drains. Drain pans shall be inspected at least once a year and cleaned if required Outside Air Flow Verification. For units >2,000 cfm the outside air flow shall be tested a minimum of every 5 years and adjustments shall be made to have the design flow provided to system Re-commission system every 5 years or sooner if possible.

36 ASHRAE 62.1 Standard is under continuous maintenance process
You can propose a change to the standard Notice of proposed changes appears in ASHRAE Standards Action You can comment on proposed changes You can request an interpretation ASHRAE 62.1 is under continuous maintenance. Using this process the standard is updated on a regular basis. Anyone can request a change to the standard. When changes are proposed to the standard, notice of the public review period is published in the ASHRAE Standards Action. Anyone from the public can comment on the proposed changes. Prior to changes, responses must be made to commenters. If there are unclear requirements in the standard, a request for interpretation may be submitted.

37 ASHRAE 62.1 User’s manual for 62.1-2007 IMC & UMC Code adoption
ALI Short Course and Professional Development Course eLearning course IAQ Design Guideline is in the works Next publication of ASHRAE 62.1, 2010 A user’s manual for is published by ASHRAE and is available at the ASHRAE bookstore at The ventilation rate procedure is adopted into the IMC. The ASHRAE Learning Institute offers short courses, a professional development course, and an eLearning course. An IAQ design guideline is being jointly developed by ASHRAE/EPA/BOMA/SMACNA/AIA/USGBG. The next scheduled full publication of the standard will be in 2010.

38 ASHRAE 62.1 update: Overview - Where are we now?
Questions? ASHRAE 62.1 update: Overview - Where are we now?

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