5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN 5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN MODULE 5 HVAC FUNDAMENTALS OF MODERN LABORATORY DESIGN Module 5 PG1
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN MODULE 5 GOAL Provide a fundamental understanding of Laboratory Heating, Ventilating and Air Conditioning Concepts and Systems Module 5 PG2
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 6 Outline • Issues • Drivers • Concepts • Systems Module 5 PG3
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Issues • “It’s too hot and humid in my lab!” Some of the most common concerns of • “It’s too cold and dry in laboratory facility users are relative to the my lab!” HVAC system, including: • “It’s like a tornado in my lab!” Module 5 PG4
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers • Laboratory Equipment Heat Generation • Air Change Rates • Containment Equipment • Occupant Gowning Requirements • Type of Laboratory and Science Module 5 PG5
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Laboratory Equipment Heat Generation Heat Generation Information • Heat is expressed in BTU/Hour • 1 Watt = 3.414 BTU/Hour • Sensible Heat: Energy Required to Change Temperature • Latent Heat: Energy Required to Remove Moisture • One Ton of Air Conditioning: 12,000 BTU/Hour or 3,515 Watts • 135 cfm of outside air equals 1 ton of cooling (Kansas City weather) Module 5 PG6
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Laboratory Equipment Heat Generation Loads for Bench Mounted Equipment (low density) Item Bench L.F. Btuh Optical Microscope 2 222 Analytical balance 2 24 Computer & Monitor 4 461 Rotary Evaporator 3 253 Total 11 960 Btuh Per Linear Foot 87 Watts per linear foot 26 Sources: ASHRAE 2001 Fundamentals Handbook Labconco Catalog Revco Freezer Data Sheets NOTE: This is heat release, not equipment nameplate electrical data Module 5 PG7
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Laboratory Equipment Heat Generation Loads for Bench Mounted Equipment (high density) Item Bench L.F. Btuh Optical Microscope 2 222 Small Centrifuge 3 304 Thermal Cycler 2 795 Fluorescent Microscope 2 700 Flame Photometer 2 365 Rotary Evaporator 3 253 Total 14 2639 Btuh Per Linear Foot 189 Watts per linear foot 55 Sources: ASHRAE 2001 Fundamentals Handbook Labconco Catalog Revco Freezer Data Sheets Module 5 PG8
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Laboratory Equipment Heat Generation Loads for Floor Mounted Equipment (high density) Item Floor L.F. Btuh Ultra Low Freezer 4 3618 Large Centrifuge 4 4014 Large Incubator 4 4556 Refrigerator 3 1672 Total 15 13860 Btuh Per Linear Foot 924 Watts per linear foot 271 Sources: ASHRAE 2001 Fundamentals Handbook Labconco Catalog Revco Freezer Data Sheets Module 5 PG9
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Laboratory Equipment Heat Generation Two Module Lab Example (484 SF): • 16 feet of space allocated for floor mounted equipment • 48 feet of bench space • Assume half the bench is full – 24’ of equipment Heat Generated using moderate density: • Bench: 138 btuh /ft X 24’ = 3312 btuh • Floor: 662 btuh /ft X 16’ = 10,592 btuh • Total: *13,904 btuh More than 1 ton of A/C • Using 100% outside air in Kansas City: 57,300 btuh (4.75 tons) *There is no diversity in this number Module 5 PG10
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Laboratory Equipment Heat Generation When figuring equipment heat gain: • Use published or measured heat release information, not electrical nameplate • Apply diversity carefully based on expected lab use • Consider sub-metering loads in similar buildings prior to planning a new lab • The answer is not “10 watts/ sq.ft .” Module 5 PG11
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Air Change Rates • 1 Air Change per Hour – The Amount of Air in Cubic Feet per Minute (CFM) it Takes to Completely Replace the Air in a Laboratory once in One Hour • CFM = (Floor Area x Ceiling Height x Air Change Rate)/60 • 135 CFM per One Ton of Cooling • Standards and Guidelines Vary from 4 to 12 AC/hr Module 5 PG12
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Air Change Rates • 2 Module Laboratory (22’ x 22’); 484 SF • CFM Requirement for varying ceiling heights and air change rates MORE IS NOT NECESSARILY BETTER Airflow in CFM at Given Air Change Rate Ceiling Height 6 8 10 12 9 436 581 726 871 10 484 645 807 968 11 532 710 887 1065 12 581 774 968 1162 Module 5 PG13
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Air Change VS. Fume Hoods • 2 Module Laboratory (22’ x 22’); 484 SF • CFM Requirement for varying ceiling Nominal Fume Hood CFM heights and air changes 5' Fume 6' Fume 8' Fume Hood Hood Hood Airflow in CFM at Given Air Change Rate 960* 1180* 1660* Ceiling Height 6 8 10 12 610** 750** 1060** 9 436 581 726 871 * Sash full open; face 10 484 645 807 968 velocity 100 fpm 11 532 710 887 1065 ** Sash at 18”; face 12 581 774 968 1162 velocity 100 fpm Module 5 PG14
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Containment Equipment Approximate Exhaust CFM for 6’ BSC • Class II Type A2 Cabinet without canopy: 0 cfm • Class II Type A2 Cabinet with canopy: 600 - 700 cfm • Class II Type B2 Cabinet : 1150 cfm (requires a dedicated exhaust fan Select the correct cabinet for the application Cabinets that use ECM motors have significantly lower heat gain and higher efficiency than PSC motors Module 5 PG15
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Air Changes VS. Containment Equipment • *Laboratories often use 4 to 6 times more energy per sq. ft. than a typical office building • *Nearly half of electrical energy used in a laboratory building can be attributed to ventilation • The decision on air exchange rates and fume hood sash position affect both first cost and lifetime building energy Annual electricity use in Louis Stokes Laboratory, costs National Institutes of Health, Bethesda, MD Courtesy of Labs 21 *Courtesy of Labs 21 Module 5 PG16
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Gowning/PPE Impact of Gowning/PPE in Laboratory • May require reduction in Laboratory Design Temperature • Reducing Design Temperature from 72 deg. F to 70 deg. F results in: • A 12% increase in cooling airflow • A 12% increase in cooling capacity Module 5 PG17
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Type of Laboratory/Type of Science Animal Holding Rooms • 10 to 15 Air Changes per hour Module 5 PG18
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Type of Laboratory/Type of Science Instrument/Computational Laboratories • High Equipment Heat Loads Module 5 PG19
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Drivers – Type of Laboratory/Type of Science Chemistry/Analytical Laboratories • High Fume Hood Density Module 5 PG20
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN MODULE 5 – BASIC CONCEPTS Laboratory Hazards Containment Flexibility & Redundancy Module 5 PG21
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Concepts – Laboratory Hazards Health Hazards • Irritants • Corrosive Substances • Allergens • Asphyxiants • Carcinogens • Reproductive Toxins • Neurotoxins Flammability Hazards Reactivity Hazards Explosive Hazards Biohazards Radioactive Hazards Module 5 PG22
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Concepts – Containment Primary Containment • First Level of Containment; typically a containment device: chemical fume hood, biological safety cabinet, etc. Module 5 PG23
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Concepts – Containment Secondary Containment • Second Level of Containment: • Laboratory Envelope • Directional Airflow • 100% Outside Air • Differential Pressure or Volumetric Offset • Doors must be kept closed • Exhaust fans run continuously Best Practices: Use Primary and Secondary Containment to Protect Personnel from Exposure to Hazards ANSI Z9.5 requires air movement from lower hazard to higher hazard Module 5 PG24
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Concepts – Containment Primary Containment Devices - Chemical Fume Hoods • Bench Mounted Chemical Fume Hoods • Each Fume Hood uses as much energy as an entire house* * From Labs 21 Module 5 PG25
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Module 5 Concepts – Containment Primary Containment Devices - Chemical Fume Hoods • Floor Mounted Chemical Fume Hoods or Ventilated Enclosures Module 5 PG26
5 HVAC FUNDAMENTALS OF MODERN LAB DESIGN Primary Containment Devices - Chemical Fume Hoods • Floor Mounted Hood Location is Critical Module 5 PG27
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