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 commentsGeneral requirementsVentilation requirementsConstruction and O/M requirementsQuestionsToday’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? PrescriptiveCommissioningO&MCombustion airFiltrationIAQ-Health disclaimersSmoking disclaimersClarified CO2as ventilation metricAlternative Air Quality Proc.Updated19701980199020002010History 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 ComfortVentilation Rate Proc.IAQ Proc.Commercial and High Rise Res.Enforceable code languageETS vent. rates not coveredVent. Rate. Proc. ModifiedOccupant and area vent. ratesfirst issued
4 ASHRAE Standard 62.1-2007 & Related Activities… Std is the most current versionIMC adopted methodology and rates in 2007 SupplementSeveral educational courses are available from ASHRAEThe 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 Purpose1.1 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 additions1.3 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&M2.3 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 retroactively2.5 Does not prescribe specific ventilation rates for smoking spacesScope 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’t2.6 Ventilation requirements based on chemical, physical, & biological contaminants2.7 Consideration or control of thermal comfort is not included2.8 Contains requirements, in addition to ventilation related to certain sourcesRead these requirements.After 2.9It 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’t2.9 Acceptable IAQ may not be reached in all buildings meeting these requirements because of special conditions notedDefinition 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 dissatisfactionIt 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 QualityMust determine NAAQS attainment statusIf nonattainment, air cleaning is required in some cases4.2 Local Air QualityConduct observational site survey to identify local sources of air contaminantsDetermine 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 DocumentationRegional air quality compliance statusLocal survey informationConclusions regarding acceptability of outdoor air qualityDocumentation 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 openings5.2 Ventilation Air Distribution.Must provide means to adjust (balance)Must be sure that mixing occurs in RA/OA mixing plenums62.1 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 pressure5.4 Ventilation System Controls. Control to assure proper ventilation under any operating condition5.5 Airstream Surfaces. Use materials that have documented resistance to microbial growth and erosion5.3 Must exhaust harmful contaminants in negative pressure ducts to prevent leakage into occupied spaces, plenums5.4 Must have controls to enable fanNoted: VAV systems with fixed dampers must comply (high % open). Leads to modulating damper and sensed OA flow5.5 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 sourcesMust comply with default minimum separation distances in Table 5-1. Examples:Loading dock 25 ftDumpster 15 ftSurface below intake ftCooling tower exhaust 25 ftMust limit rain water penetration (using hood, proper velocity, etc.) or manage water that penetratesMust use bird screens and prevent bird nestingThis 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 outdoors5.8 Combustion Air. Provide combustion air and exhaust air for indoor fuel-fired appliancesProducts 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 streamMinimum 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 conditionException 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 condensation65% RH limit62°F DPThe 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 carryoverSlope: 1/8” per foot toward outletDrain: At lowest point, large enough to prevent overflowDrain 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 carryoverDrain pans must drain
19 General Requirements 5.0 Systems and Equipment 5.12 Finned Tube Coils and Heat ExchangersUse drain panSelect to limit coil pressure drop to fpm face velocityIf higher pressure drop, provide access on both sides for maintenance
20 General Requirements 5.0 Systems and Equipment 5.13 Humidifiers and Water Spray SystemsUse potable water (or better)No downstream devices within absorption distance5.14 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 SurfacesWeather barrier to prevent water penetration into envelopeVapor retarder or other means to prevent condensation on cold surfaces within envelopeSeal all seams, joints, penetrations to limit infiltrationInsulate pipes, ducts expected to have surface temperature below surrounding dew pointAlthough 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 exhaustMaintain garage pressure at or below adjacent occupied spaceOr, use a vestibuleOr, 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” spacesClassification - Designate air leaving each space using Table 6.1Class 1: Low contaminant concentration (office)Class 2: Moderate concentration (dining room)Class 3: Significant concentration (sick room)Class 4: Highly objectionable or potentially harmful concentrationNote 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 ClassificationManage recirculation as followsClass 1 to anywhereClass 2 to self, similar Class 2 or Class 3 or Class 4Class 3 to selfClass 4 to outdoors
25 General Requirements 5.0 Systems and Equipment Re-designation of air classAir Cleaning. May reclassify air cleaned by passing it through an appropriate air-cleaning systemTransfer. 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 3Transfer 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-FreeAir must be kept separate by means of walls, automatic door closers and pressurizationPressurization. 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 prohibitedETS areas must be exhausted to the outdoorsThe 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 systems6.1.1 Ventilation Rate Procedure. Prescribes rates & procedures based on typical space contaminant sources & source strengthsThis 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 PhaseDon’t operate air handlers without filtersProtect building materialsProtect occupied areasLimit migration of construction contamination into occupied spaceSpeaker 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 systems7.2 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 OwnerThe 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 Manual8.4 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 requiredOutside 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 systemRe-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 standardNotice of proposed changes appears in ASHRAE Standards ActionYou can comment on proposed changesYou can request an interpretationASHRAE 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 CourseeLearning courseIAQ Design Guideline is in the worksNext publication of ASHRAE 62.1, 2010A 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?