October 4, 2007 Charleston, SC
DesigningDesigning forfor ActualActual NotNot TheoreticalTheoretical HVACHVAC RequirementsRequirements inin LaboratoryLaboratory FacilitiesFacilities
J.J. PatrickPatrick Carpenter,Carpenter, PEPE PrincipalPrincipal VV aa nn dd ee rr ww ee ii ll EE nn gg ii nn ee ee rr ss WhatWhat AreAre LaboratoryLaboratory FacilitiesFacilities ??
Places of Uncertainty
Places of Risk
Sources of Contamination
How does the degree of each element vary among lab types?
How does or should the variation impact the design criteria? Vanderweil Engineers TypicalTypical LabLab DesignDesign IssuesIssues Primary issues and strategic design elements considered:
z Fume Hoods (capture and dilution)
z Room Ventilation (dilution and distribution)
z Cooling Loads (connected … diversity … runtime)
z Room Pressurization (volume differential)
z Duct Distribution (transport)
z Exhaust Stacks (dispersion)
Vanderweil Engineers StandardStandard ofof CareCare …… Conventional Conventional Wisdom?Wisdom? Why is Conventional considered… Wisdom?
While Innovation and Ingenuity are considered … Risk taking?
Most lab designers know or understand little of the reasons why the industry “standard of care” came about … They just know that if they follow those practices and apply them appropriately, their backs are covered … and their insurance underwriters are happy. Inevitably this approach lead to success measured more by “Does It Work” than by “How Well Does It Work”?
Vanderweil Engineers HistoricalHistorical PerspectivePerspective VERY early Laboratories
Vanderweil Engineers HistoricalHistorical PerspectivePerspective VERY early Hoods and Less than safe practices …
Vanderweil Engineers FrustrationsFrustrations Unknown and unknowable = indeterminate environments indeterminate nature of the work being done in labs:
z Varied chemicals
z In varied quantities
z Handled with varied procedures
z Resulting in varied hazards
z Fear or distrust of monitoring & control systems: Ê Questionably Relevant information Ê Eventually Inaccurate information Ê Potentially Unreliable information
Vanderweil Engineers WhatWhat areare thethe DominantDominant DriversDrivers ofof DesignDesign forfor LabsLabs Conservatism: Fear, uncertainty, ignorance, simplification, Risk / litigation averse, fee-limited, Defensive Codes and Standards: Life safety / Health & Safety … protecting the Public mostly ignoring costs … paybacks aren’t any option when it comes to lives! Psychology: One mistake is Remembered Long After an almost Endless String of Successes! Standard of Care: Tends to raise the bar of expectations … usually based more on perception than proof or Science.
Vanderweil Engineers StandardStandard PracticesPractices OrOr “Rules“Rules OfOf ThumbThumb Derived from historical environments …dissimilar to today’s
Given the uncertainty in labs, the challenges of providing safe, comfortable and controlled environments requires conservative approaches that Result in More! Ê More airflow Ê More velocity Ê More air changes Ê More outside air Ê More capacity Ê More investment Ê More energy
Vanderweil Engineers Engineer’sEngineer’s IdeaIdea ofof RightRight SolutionSolution
Will I have enough capacity? Getting it Big Enough is Easy!
Vanderweil Engineers What’sWhat’s DifferentDifferent RecentlyRecently thatthat ImpactsImpacts ourour ApproachesApproaches Technology
z Information … about building operation
z Monitoring and sensing technologies Sustainability
z Focus on Demonstrable Performance
z Rationalize less conservative / more responsive approach Intent:
z Better define goals in more direct terms
z Link goals to more easily correlated performance criteria
z Integrate capacity, measurement and control to achieve more performance based approaches
Vanderweil Engineers HeightenedHeightened SensitivitySensitivity andand AwarenessAwareness Buildings and Systems as
z Impact on the Environment
z Utilization of Resources and Energy
z Delivering “Performance” Ê Capacity Ê Capability Ê Quality Ê Accuracy Ê Reliability Ê Flexibility
Performance is more than Adequacy and Efficiency!
Vanderweil Engineers SoSo WhereWhere areare wewe andand WhereWhere areare wewe Going?Going? We’ve learned: How to Do Complex Calculations & Analyze Options … But will Our Criteria / Assumptions of Operations & Use Give Us Appropriate Accuracy? How to Manipulate Large Amounts of Data … But do we Understand it and use it Effectively? How to Justify our Preconceptions … But are our Solutions Responsive? How to Verify and Validate Performance … But Have we Properly Defined Performance?
Vanderweil Engineers ActualActual LabLab PowerPower TrendingTrending
g( q ) 4.0
1SB1 1SB2
3.5 2SB1 2SB2 EMERGENCY POWER READINGS
3.0
2.5
2.0 Watts / Net Sq. Ft.
1.5
1.0
0.5
0.0 1:00 PM 2:00 PM 3:00 PM 4:00 PM 5:00 PM 6:00 PM 7:00 PM 8:00 PM 9:00 PM 7:00 AM 8:00 AM 9:00 AM 1:00 AM 2:00 AM 3:00 AM 4:00 AM 5:00 AM 6:00 AM 12:00 PM 10:00 PM 11:00 PM 10:00 AM 11:00 AM 12:00 AM
Vanderweil Engineers 5,000 50.0%
4,500 BuildingBuilding && SystemSystem DynamicsDynamics …… Performance Performance vs.vs. SizingSizing 45.0%
4,000 Minimum 40.0% Max imum Average % Design Flow
3,500 35.0%
3,000 30.0%
2,500 25.0% M
2,000 20.0% Fume Hood CF Hood Fume
1,500 15.0%
1,000 10.0%
500 5.0%
0 0.0%
Vanderweil Engineers 140%
LaboratoryLaboratory ExhaustExhaust AirflowAirflow TrendingTrending 120%
This upper plot compares the actual total lab exhaust airflows with theoretical minimum flows based on terminal box minimums.The very tight band (7%-25% above min.) indicates that most boxes are operating near their design minimums. Laboratory Exhaust Airflow Trending The turndown ratios of the hooded (chemistr y) labs are about 3.4 to 1 while the Biolo gy labs are desi gned for about 1.6 to 1! March 2-8, 2002 100% Flows as % of Design Minimums
80% Flows as % of Actual Maximums
This middle plot compares the actual total lab exhaust airflows with the maximum flow measured over the period of trending. Fundamentally, it shows three primary points: 60% 1. The days and nights are very consistent with less than a 15% turndown for nights and weekends. 2. There is a clear but gradual increase / decrease in airflows with builidng occupancy during the day. 3. There is a mid-day "dip" in airflows that is caused totally by the fume hood driven labs indicating that sashes are being close and that the "proximity" control sensors are reinforcing the airflow reductions. Exhaust Airas % Flow 40%
This lower plot compares the actual total lab exhaust airflows with the theoretical maximum flows based on terminal box capacities. Flows asThe very% tight of (37%-43%)Design band Maximums around 40% of the box totals indicates that the fans are probably oversized. There will be seasonal 20% increases in these flows as builidng envelope loads impact some spaces, however these changes are probably relatively minor with likely no more than a 10-15% change resulting in a band about the 45% level. This confirms previous trending which suggests that the systems operate esssentially year round at 50% or less of their capacity!
0% 1:00 7:00 1:00 7:00 1:00 7:00 1:00 7:00 1:00 7:00 1:00 7:00 1:00 7:00 1:00 7:00 1:00 7:00 1:00 7:00 1:00 7:00 1:00 7:00 PM PM AM AM PM PM AM AM PM PM AM AM PM PM AM AM PM PM AM AM PM PM AM AM
Vanderweil Engineers SoSo What’sWhat’s FirstFirst …… and and What’sWhat’s Left?Left? Need complete, comprehensive, thorough and all-inclusive Definition Of Needs …in Fundamental Terms!
Get back to basics … before assumptions … before preconceptions … before prejudices ... before traditions … before prior limitations …
Understand and justify all decisions based on the Fundamentals.
Vanderweil Engineers Codes,Codes, RegulationsRegulations andand StandardsStandards
OSHA 29 CFR 1910.1450Occupational Exposure to Hazardous (1990-1996) Chemicals in Labs ANSI Z 9.2 (2001) Local Exhaust Ventilation Systems Z 9.5 (2003) Laboratory Ventilation NFPA 45 (2004) Fire Protection … for Labs Using Chemicals ICC/IMC 510 (2003/06) Hazardous Exhaust Systems ASHRAE 62.1/.2 (2004) Ventilation for Acceptable Indoor Air Quality 90.1 (2004) Energy Standards for Buildings 110 (2007?) MOT Performance of Lab Fume Hoods NSF 49 (2004) Class II (Laminar Flow) Biosafety Cabinetry SEFA 1 (2006) Lab Fume Hoods Recommended Practices ASHRAE (2002) Laboratory Design Guide LBNL Ver. 4 (2003) Design Guide for Energy-Efficient Research Laboratories
Vanderweil Engineers HazardousHazardous MaterialsMaterials requirerequire Hoods,Hoods, Snorkels,Snorkels, DisposalDisposal
Vanderweil Engineers BiologicalBiological SafetySafety …… Safety Safety CabinetsCabinets areare anan IssueIssue
Vanderweil Engineers SomeSome LabsLabs areare Equipment/ProcessEquipment/Process DrivenDriven …… Exhaust? Exhaust?
Vanderweil Engineers EvolutionEvolution ofof DilutionDilution RequirementsRequirements Early approaches influenced by lack of Hoods or poor performance Before A/C, lab had no “supply concept” … only a source of make-up air … through doors or windows As Fume Hoods became standard, ways to ascertain their effectiveness established exhaust airflow benchmarks Fume Hood Performance … influenced by “supply” concepts indirectly drove distribution concepts but without science to optimize approaches Room “ventilation” without scientific basis … standards and guidelines gave no directed guidance … only generalizations Evolution of dilution concepts, mixing effectiveness and CFD modeling improved understanding of airflow concepts in rooms. Move towards “effectiveness” concepts.
Vanderweil Engineers TheThe VocabularyVocabulary ofof LabLab VentilationVentilation Room Ventilation for … Removal of Pollutants or Contamination
z The ability of the supply air to improve room air quality
z Ventilation Efficiency … relates more to <100% “clean” air
z Mixing Effectiveness … (increased Turbulence)
z Age of Air
z Ventilation Effectiveness Ê Air Quantity Ê Supply Air Distribution Ê Exhaust Air Collection
z Static or Steady State Assumptions vs. Dynamic Effects Air Change Rates are not necessarily related to the Removal or Dilution Per ANSI Z9.5: “Not an Appropriate Concept for designing contaminant control systems!”
Vanderweil Engineers RoomRoom VentilationVentilation Reference Standards
z Prudent Practices … 6–12 ACPH
z NFPA 45 - 8+ ACPH (Occupied) 4 ACPH (Unoccupied)
z ASHRAE Handbook 6–10 ACPH
z OSHA … 4–12 ACPH Comparison Values
z Typical Office 1 ACPH (Supply = 7 ACPH)
z Animal Room 10–20 ACPH
Target Minimum Air Changes (given what assumptions?)
z Occupied 6-10 ACPH
z Unoccupied 2-4 ACPH
Vanderweil Engineers EvolutionEvolution ofof DilutionDilution RequirementsRequirements
Room airflow concepts had no strong regulatory direction Air quantities were assumed related to maintaining a safe environment BUT labs were presumed potentially contaminated and therefore negative pressurization was deemed necessary Airflows were clearly inadequate to handle “events” or spills … but airflows were still kept at artificially higher levels … no sound basis to reduce them. Assessments of critical dilution needs continued to focus on fume hoods (LEL purge) and discharge stack dispersion to minimize external contamination or re-entrainment Energy cost pressures continued to force gradual reductions in normal and unoccupied airflow requirements
Vanderweil Engineers EvolutionEvolution ofof RoomRoom AirflowsAirflows forfor DilutionDilution Equiv. Equiv. Occupied Unoccup. Average CFM/SF CFM/SF ACPH ACPH ACPH Occupied Unoccup. 12 12 12 1.8 1.8
12 8 9.33 1.8 1.2
10 6 7.33 1.5 0.9
8 4 5.33 1.2 0.6
9 Ft Ceiling Height 1/3 : 2/3 Occupied to Unoccupied assumed
Vanderweil Engineers EvolutionEvolution ofof AirflowsAirflows forfor CoolingCooling LoadsLoads Early assumptions driven by explosion of electronics Heat loads were trying to follow “Moore’s” Law Facility Planning for “tomorrow” followed “Doomsday” concepts to excessive expectations of heat loads Early conservatism in cooling encouraged by comparable spiral in airflows for fume hood exhaust makeup airflows Realities did not support the overdesign approaches Energy impacts before dawn of VAV concepts were big driver in emerging panic of engineering gone wild! Emergence of VAV concepts allowed consideration of “diversity” concepts …made conservatism for “future” feasible and cost- affordable if not cost effective Energy cost pressures compounded with VAV opportunities forced closer looks at actual conditions to benchmark realistic provisions. Beginning of “Right-Sizing”
Vanderweil Engineers EvolutionEvolution ofof AirflowsAirflows forfor CoolingCooling LoadsLoads
Corollary improvements in scientific equipment and Energy Star concepts encouraged mitigation of spiraling heat load. Costs of Scientific Equipment result in increasing shared resources and consolidation of high heat sources … easing general trend to increase cooling ability in all areas. Overwhelming support for Sustainability focused renewed attention on both Energy Use and Resource Conservation. Industry Energy Benchmarking (Labs21) increases “peer” pressures to justify project criteria. Repeated success and verification of “real” data and impacts of proven operational “diversity” become industry standard for validation of user needs. LEED prominence encourages further conservation instead of conservatism and drives further efforts for M&V
Vanderweil Engineers EvolutionEvolution ofof RoomRoom AirflowsAirflows forfor CoolingCooling
Resulting Resulting Equipment Total Cooling Cooling Exhaust Load Density Density Airflows Airflows Watt/sf Watt/sf CFM/sf CFM/sf
10 14 3+ 3.5+
15 19 4+ 4.5+
20 24 5+ 5.5+
4-8 6-10 1.3-2.2 1.7-2.6
Vanderweil Engineers EvolutionEvolution ofof AirflowsAirflows forfor ExhaustExhaust Make-upMake-up Initially driven by Fume Hood Design concepts
z Baffling options
z Impact of exhaust connection configuration
z Bypass concepts to stabilize velocities
z Airfoil inlet improvements Exploding research increases fume hood & Exhaust Air
z Densities
z Sizes
z Sash openings Fume Hood performance research and testing standards stabilize and focus design directions on concepts
z Excess face velocities loose favor
z Impacts of room conditions increase focus on supply air concepts
Vanderweil Engineers EvolutionEvolution ofof AirflowsAirflows forfor ExhaustExhaust Make-upMake-up Energy Issues drive alternatives
z Auxiliary air concepts … later shown as wrong move
z Combination Sash concepts … lower effective sash areas and resulting airflows
z Consideration of alternate criteria for set-up modes
z VAV/diversity concepts improve options for right-sizing
z Improved inlet conditions and Reduced sash areas
z Sash closing concepts to reduce opening and flows Industry Guidelines (esp. Z-9.5) shift focus to Verified Performance based concept for hoods instead of just FV Expanding use of Fume Hood Performance Testing creates better understanding of External Influences on Hood
Vanderweil Engineers EvolutionEvolution ofof AirflowsAirflows forfor ExhaustExhaust Make-upMake-up
Maturity & increasing acceptance of VAV concepts leads to:
z Improved methods to detect fume hood face velocity on a real time basis aid in user feedback
z Concerns about response times of control systems
z User presence or in use detection allows reset of fume hood airflows for changing face velocities
z Evolution of testing protocols to address dynamics Other refinements in Fume Hood design evolve from more sophisticated performance testing:
z Impacts of Vortex concepts in Hoods
z Importance of Hood depth on overall containment
z Sensitivity to Cross currents and Turbulence “High Performance” hoods … lower Face Velocity
Vanderweil Engineers EvolutionEvolution ofof AirflowsAirflows forfor ExhaustExhaust Make-upMake-up Mainstream acceptance of VAV concepts reinforces value in manifolded systems because of
z Opportunity to take advantage of diversity
z Ability to improve reliability with partial redundancy
z Ability to improve reliability with emergency power
z Ability to improve overall dilution and dispersion EH&S develop better appreciation for advantages Codes, esp. fire, create conflicting perspectives forcing compromise definition of “lab scale” use of materials Duct, shaft and dampering concepts still somewhat in flux because of differing opinions and interpretations by AHJs Uncertainty limits some applications of manifolding
Vanderweil Engineers EvolutionEvolution ofof RoomRoom AirflowsAirflows forfor ExhaustExhaust (6(6 FTFT hoods)hoods) Sash Face Exhaust Sash Dimensions Area Velocity Airflows Width x Height SF FPM CFM 62 x 30 12.9 100 1300
62 x 18 7.7 100 775 62 x 30 12.9 60 775 2 @ 16 x 30 6.7 100 670 62 x 18 7.7 80 620 62 x 18 7.7 60 465
Vanderweil Engineers EvolutionEvolution ofof AirflowsAirflows forfor ExhaustExhaust Make-upMake-up Impacts of Hood Exhaust Airflows at current minimums
z 6 Ft hood w/ lower face velocity & sash area < 500 CFM!
z Assuming one FH per (2) 250 SF modules = < 1.0 CFM / sf
z Actual Exhaust flow of 0.9 CFM/SF ~ 6 ACPH (9’ ceiling)
z Well below most occupied standards for ACPH
z Provides about 0.7 CFM/SF for supply with balance from transfer into room (negatively pressurized lab!)
z Results in less than 3. 5 watts/SF cooling!
z Dilution and Cooling now dominate airflows!
z With unoccupied ACPH at 4.0, Hood has little turn-down! Even at twice the density (1 hood / module), 12 ACPH exhaust => 10.5 ACPH supply = 7 watts cooling capacity!
Vanderweil Engineers OtherOther ConsiderationsConsiderations Current Fume Hood Exhaust minimums for LEL require about 250-300 CFM for 6 Ft hood depending on depth This only allows Fume Hood turndown of about 50%! Are there options to monitor this and allow further reductions under most normal conditions?
Vanderweil Engineers SoSo WhereWhere AreAre WEWE NowNow andand WhereWhere areare WeWe GoingGoing?? At current flows, limits of cooling & FH exhaust not likely to reduce but FH performance will be closely watched BUT … lower flows may force closer scrutiny of contaminant concentrations in labs Reduced flows means room air distribution is critical to:
z “Effectively” ventilate space & dilute contamination
z “Effectively” provide comfortable space conditions With Low Flows & good hood containment, little room contamination or need for it under normal conditions BUT Requirements for Upset or spill scenario conditions may force reconsideration of how to increase flows (purge) Evolving EH&S sensitivity may move towards more direct assurance of “safe” lab conditions with active monitoring
Vanderweil Engineers AssessingAssessing HowHow CloseClose toto MinimumMinimum ConditionsConditions YouYou AreAre Following issues and questions suggest a checklist of considerations that are essential to establish realistic and practical limits of “right-sizing” a lab exhaust system. Evaluation process needs comprehensive team approach AND thorough understanding of current and future needs benchmarked by good data on existing operations Key issues to achieving this optimization:
z Commitment to monitor and maintain requisite Good Lab Practices by conscious and informed users
z Commitment to monitor and maintain corresponding measurement and control systems that provide performance and diversities that make concepts possible
Vanderweil Engineers DesignDesign ImplicationsImplications ofof LabLab ObjectivesObjectives Promote Health and Safety z Provide Adequate Containment = Optimize FH Face Velocity? z Limit Sash Opening? z Consider options to excessive Minimum Hood Airflows? z Provide Room (and Hood) Dilution = “Improve” Airflow Effect? z Provide Stability = Use Constant Air Volumes? z Maximize Exhaust Dispersion = Maintain Min. Stack Velocity? z Maximize Separation? … Stack Heights & Locations? Manifold? z Increase Exhaust System Reliability = Redundant Fans? EPS? z Minimize Complexity to Insure Proper Operation/Maintenance? Codes z Any specific code Restrictions on things such as Manifolding? z Limits on Fume Hood Velocities (in use / not in use)? z Performance Testing of Fume Hoods Provide Comfort / Conditioning z What Current vs. Future Equipment Heat Loads are required? z Does any Equipment have Increased Temperature Sensitivity? Vanderweil Engineers EssentialEssential DesignDesign QuestionsQuestions traditionallytraditionally AddressedAddressed Is the Lab an “Air” Driven Environment?
z Do fume hoods /exhaust devices dictate room airflows?
z Do materials and procedures dictate certain minimum room air dilution rates = ACPH, mixing effectiveness?
z Are space loads significant enough to drive supply air?
z Are they continuous or daily or seasonally variable?
z Are space temperatures lower because of gowning
z Do cooling needs depress required cooling coil temps?
z Do Activities really require labs to be negative pressure?
z Is space pressurization required at All times? Is Lab a 100% Exhausted Environment?
z Are materials / risks (potentially) present at All times?
z Are Lab “dynamics” (effectively) monitored?
Vanderweil Engineers EssentialEssential DesignDesign ConsiderationsConsiderations (Cont’d)(Cont’d) How does Occupancy affect airflows?
z Will Laboratory really be an “Occupied” space?
z How often are people present and for how long?
z Will labs be automated? Laboratory Monitoring
z Can or is the occupancy monitored?
z How well “monitored” are Lab activities?
z Is monitoring continuous and alarmed?
z How effective is the sensing?
z Can airflows & effectiveness of “ventilation” be tracked? Environmental Control
z How critical is space temperature and humidity control?
z How critical is air cleanliness?
z Is increased filtration a requirement or option?
Vanderweil Engineers MajorMajor CodeCode DriversDrivers inin LabsLabs –– Basics Basics … ensure that chemicals originating from the laboratory shall not be recirculated. Lab hood face velocities and exhaust volumes … sufficient to contain contaminants generated within the hood …provide containment of the possible hazards and protection for personnel at all times when chemicals are present in the hood. Air exhausted … shall be discharged … sufficient to prevent re- entry of chemicals & prevent exposures to personnel.
Vanderweil Engineers ConceptualConceptual ModelModel ofof CapacityCapacity andand EnergyEnergy ImpactsImpacts ofof ConservatismConservatism inin DefiningDefining LabLab VentilationVentilation NeedsNeeds Basic Design Considerations
z Space Equipment (and Lighting) Heat Load Density
z Ventilation Rates (ACPH), Occupied and Unoccupied
z Fume Hood and Device Exhaust Make-up Air Ê Sash Area (In Use, Set-up, Not In Use?) Ê Face Velocity Ê Minimum flows under NO load or no containment?
z Diversities (equip and hood) for Room and System
z Room Pressurization
z Hours of Operation
z Duct and Stack Velocities
z 100% Exhaust OR selective recirculation? Above Considerations have Normal (occupied/unoccupied) Conditions and Off-Normal (Spill) Conditions
Vanderweil Engineers GASGAS CONTAMINANTCONTAMINANT DILUTIONDILUTION OVEROVER TIMETIME
MixingMixing CoefficientCoefficient K=5K=5 100%100%
90%90%
80%80% 11 ACPHACPH (Office)(Office) 55 ACPHACPH (Hospital)(Hospital) 70% 70% 1010 ACPHACPH (Bio.Lab)(Bio.Lab) 2020 ACPHACPH (Lab/Clean)(Lab/Clean) 60% 60% 4040 ACPHACPH (Lab/Clean)(Lab/Clean) 6060 ACPHACPH (Chem.Lab)(Chem.Lab) 50%50%
40%40% % Concentration % % Concentration % 30%30%
20%20%
10%10%
0%0% 00 102030405060 102030405060 TimeTime inin MinutesMinutes
Vanderweil Engineers AverageAverage CoolingCooling LoadLoad (from(from lightslights && equip.equip. heatheat gain)gain) 80%
These Profiles are for Weekdays 70% only. Weekends / Holidays are assumed to be constant (24 Chem Lab areas hrs/day) at weeknight levels. 60%
50%
Animal Holding / Procedure areas 40%
30%
Non-Chem Lab areas 20% % of Max Space Equipment Load Equipment Space Max of %
10%
0% 1 AM 3 AM 5 AM 7 AM 9 AM 11 AM 1 PM 3 PM 5 PM 7 PM 9 PM 11 PM Time of Day Vanderweil Engineers Vanderweil Engineers AIRFLOWAIRFLOW VARIATIONVARIATION withwith CONTROLCONTROL OPTIONSOPTIONS
HighHigh ConstantConstant VolumeVolume AirAir ChangesChanges // HourHour 2525
HighHigh 2-Position2-Position 2020 ConstantConstant VolumeVolume Avg.Avg. ConstantConstant VolumeVolume
1515 Avg.Avg. 2-Position2-Position ConstantConstant VolumeVolume VariableVariable VolumeVolume
1010
55
00 00 2 2 4 4 6 6 8 8 1012141618202224 1012141618202224 Vanderweil Engineers TimeTime ofof DayDay GENERALIZEDGENERALIZED LABLAB FACILITYFACILITY AIRFLOWSAIRFLOWS
EXHAUST EXHAUST PERSONNELPERSONNEL CORRIDORCORRIDOR SUPPLYSUPPLY oror OFFICESOFFICES
OFFICESOFFICES oror SUPPLYSUPPLY PERSONNELPERSONNEL CORRIDORCORRIDOR
SUPPLYSUPPLY
LABORATORIESLABORATORIES
EXHAUSTEXHAUST
SUPPLYSUPPLY ? SERVICESERVICE CORRIDORCORRIDOR EXHAUSTEXHAUST
Vanderweil Engineers FanFan // StackStack Schemes:Schemes: IndividualIndividual StacksStacks withoutwithout Make-upMake-up AirAir
3,000 FPM Min. Velocity
Isolation Dampers (Typical) 10 Ft. Minimum
EXHAUST AIR from HOODS and SPACES
Vanderweil Engineers FanFan // StackStack SchemesSchemes :: CombinCombineded StacksStacks withoutwithout Make-upMake-up AirAir
3,000 FPM Min. Velocity
PENTHOUSE ROOF 10 Ft. Min.
Isolation Dampers (Typical)
EXHAUST AIR from HOODS and SPACES MAKE-UP AIR
Vanderweil Engineers Vanderweil Engineers AlternateAlternate FumeFume HoodHood ExhaustExhaust SystemsSystems -- FLOOR FLOOR MANIFOLDMANIFOLD 22
ROOF
THIRD
SECOND
FIRST
Vanderweil Engineers CentralCentral ExhaustExhaust SystemsSystems …… Redundancy Redundancy
Vanderweil Engineers
Climate: Temperature DB % Capacity for Future? #15 Humidity / WB % Redundancy? #16 Exhaust Stack Wind Speed / Dir Velocity #19 Frequency % Safety Factor? #17 % Diversity Factor? #18 % OA Supply Air Supply Treatment Fan SP Supply Duct % BP S.P. Loss #2 #4 #14 #13 #1 #3 Supply Air Control #5 Exhaust Duct Room Activity: & Treatment S.P. Loss Normal vs. Spill Event #20 Transport Velocity #12 #6 Exhaust Air Room Conditions: Transfer Air : Control Temperature Pressurization #11 & Treatment Humidity #8
Fume Hood Airflows: Equipment Sash Area Heat Gains Face Velocity Minimum Airflow #7 Control Concept Room Air Distribution and Ventilation Rate #10 #9
Conventional Typical Target No. Parameter Units Range Range 1 Percentage of Outside Air % 50 to 100 Supply Air Treatment: CooliCoolingng Temperature (DB) °F 50 to 57 Supply Air Treatment: Heating Temperature (DB) °F 54 22 Supply Air Treatment: HumidificaHumidificationtion (Room DP Temperature) °F 28 to 51 Supply Air Treatment: Filtration % 85 to 95 3 Supply Fan Static Pressure In. w.g. 5 to 8 4 Supply Duct S.P. Loss In. w.g. 2 to 4 5 Supply Air Terminal CCoontrolntrol and Treatment Y/N PI / Reheat / Filter Room Air Distribution and VentilaVentilationtion Rate - Occupied ACPH 4 to 12+ 6 66 Room Air Distribution and VentilaVentilationtion RateRate - UnoccupiedUnoccupied ACPH 2 to 8 2 7 Transfer Airflow for PressurizationPressurization CFM 100 to 200 0 to 100 Room Conditions: Temperature °F 70 to 75 72 88 Room Conditions: RelatiRelativeve Humidity % 20 to 50 30 9 Equipment Heat Gains watts/SF 5 to 20 varies Fume Hood Airflows: Sash Area % Full 50 to 100 60% Fume Hood Airflows: Face Velocity FPM 50 to 100 60 1010 Fume Hood Airflows: Minimum Airflow CFM/SF 25 much lower! Fume Hood AirflowsAirflows:: ControlsCContontrolsrols ConceConceptpt ((Dynami(Dynamics)Dynamicscs)) CV CV // 2Pos2Pos // VAVVAV VAV VAV 11 Exhaust Air Terminal Control and Treatment Y/N Press.Independent 12 Exhaust Duct Transport VelociVelocityty = S.P. Loss FPM 1200 - 2000 low 13 Exhaust Stack Velocity FPM 3000 1000 / 3000 14 Percentage Exhaust Fan Bypass Air % varies 15 Percentage for Future % 0 to 25 0 16 Percentage for RedundancyRedundancy (m(mostlyostly on Exhaust) % 0 to 50 17 Percentage for Safety Factor % 0 to 15 5* 18 PercentagePercentage for DiversitDiversityy FactoFactorr % % 7070 toto 9090 65* 65* Climate: TemperatureTemperature - Dry Bulb °F varies Climate: Temperature - Wet Bulb / Humidity °F varies 1919 Climate: Wind Speed & Direction (Rose) mph / ? varies Climate: StatisticalStatistical FreFrequencyquency ((cooling)cooling) % % 0.40.4 toto 1.01.0 ??? ??? 20 Room Activity: Normal vs. Spill Event N/S varies (spill) normal? InsightsInsights Change will always happen! Seek First to Understand … Then to Communicate! Learn to Ask the Right Questions, both those without obvious answers and those with obvious answers! Learn to recognize “Right” answers … that define “performance”
z Capacity, Capability – What conditions?
z Quality, Accuracy – What frequency?
z Reliability, Flexibility – What impacts?
z Normal & Abnormal Needs – How Achieved? Intelligent Designs are defined more by Their “Insight” than their “creativity”! … creativity gave us the “Edsel”!
Vanderweil Engineers Good Luck with Your Next and Current Projects!
QUESTIONS?
J.J. PatrickPatrick Carpenter,Carpenter, PEPE [email protected]@vanderweil.com
Vanderweil Engineers