NIH Design Requirements Manual1

Section 6.1

Section 6.1 HVAC DESIGN

6.1.0 General

6.1.1. Heating, Ventilation, and Air-Conditioning Systems for NIH Facilities

  1. Heating, ventilation, and air-conditioning (HVAC) systems for NIH Facilities shall be designed to achieve the following general criteria:

(a)Maintain space temperature and humidity at the required set points and filtration at prescribed levels.

(b)Be reliable, redundant and operate without interruption.

(c)Meet Federal sustainable design and energy conservation standards and provide a proper control system.

(d)Maintain prescribed space background noise criteria, generated by HVAC systems.

(e)Provide ventilation to remove fumes, odors, and airborne contaminants.

  1. Laboratory spaces and animal facilities shall meet the requirements in the “Biosafety in Microbiological and BiomedicalLaboratories” published by Center for Disease Control and Prevention and NIH.
  1. Animal Facilities shall meet the requirements in the “Guide for the Care and Use of LaboratoryAnimals” published by the Institute of Laboratory Animal Resources.
  1. The design of teaching Laboratories shall be based on function and on the hazard assessment made in conjunction with the users and DOHS.
  1. The design of Clinical Laboratories located within the hospital environment shall be based on the Facility Guidelines Institute (FGI) standards and ventilation shall follow the latest ASHRAE 170 standards.Where infectious samples or biohazard materials or hazardous chemicals are involved, the A&E shall follow appropriate requirements per the NIH Biosafety levels, the DRM requirements for laboratories and consult with user and DOHS. Data Center design shall follow the latest ASHRAE standards and the NIH Guidelines for Data Center located in Appendix.
  1. The Pharmacy and Radio-pharmacy shall comply with (US Pharmacopeia) USP-797 guidelines. The Drug/Bio-pharmaceutical manufacturing/processing used for human clinical trials shall follow the cGMP (Good Manufacturing Practice) and applicable CFR, (Code of Federal Regulation), ICH(International Conference on Harmonization) and FDA (Federal Drug Administration) guidelines.
  1. The design of administrative buildings and spaces shall be based ASHRAE standards, and will comply with latest International and local mechanical codes. Specific requirements for the administrative areas are included in the Office Fit Out Guidelines located in the Appendix.

The general criterion appliesto all NIH facilities including non-laboratory and non- animal areas. For NIH facilities, the non-labs and non-animal research areas shall also comply with the associated standards, local codesand guidelines attached in the Appendix of this document. For example, the ventilation requirements for offices shall follow the latest ASHRAE 62.1 standards

Teaching laboratories are different from research laboratories since they typically do not involve on-going research, the hazard level and operating hours may be lower for teaching laboratory and teaching labs may tolerate shutdowns for replacement and maintenance. Hence the redundancy requirements for research laboratories may not be applicable for teaching laboratories. Where teaching laboratories are also used as research laboratories, the requirements of research laboratories will apply.

The pharmacy and Radio-pharmacy shall comply with (US Pharmacopeia) USP-797 guidelines. Drug/Bio-pharmaceutical manufacturing/processing for clinical trials shall follow the cGMP (Good Manufacturing Practice) and applicable CFR and FDA guidelines.

6.1.2. Cognizance of DRM and Associated Standards

The A/E shall be cognizant of additional requirements in other sections of the DRM, as well as associated standards as applicable to the facility type.

Many requirements related to HVAC systems are discussed elsewhere in the DRM and in referenced standards. Basic requirements are covered in codes and standards, and additional requirements may be found in related referenced documents. The A/E must be cognizant of these requirements and coordinate with other disciplines to provide DRM compliant and appropriate design.

6.1.3. Applicable Codes and Standards:

The A/E shall comply with the design and safety guidelines and references listed in Appendix A as well as other requirements received or directed from the NIH Project Officer or required by the program. The A/E shall utilize the latest editions of referenced codes, standards, and design and safety guidelines available at the time of the design contract award.

In cases of conflict between the adopted or selected code/ standard and the NIH DRM, the most stringent, technically appropriate, and conservative criteria shall apply. The code is typically a minimum standard, and in many cases the DRM is most stringent. Where it is unclear which criteria are to be applied, application for clarification may be made through the project officer.

There are numerous industry guidelines and standards that must be followed in concert with the NIH Design Requirements Manual. Projects in the leased buildings in Maryland shall be in conformance with both DRM and the Code of Maryland Regulations (COMAR) unless otherwise noted. NIH allows waiver on DRM requirements on leased buildings based on the length of the leased. Refer to leased facility waiver checklist in the Appendix X for additional information.

6.1.4.General Planning Requirements

The arrangement of HVAC systems shall ensure maximum reliability, operational flexibility, and capacity for renovation without affecting other areas or interfering with research; shall allow service to occur outside critical and clean spaces without interfering with research; consider service access restrictions and security requirements; and shall minimize potential for disruption due to single point failures and routine maintenance. Designs shall accommodate future program renovations, expansions, serviceability, and changes of equipment. System designs must consider future capacity allowances and a cognizance of future expansion and renovation strategies, including forethought in the sizing and arrangement of utility services, main and branch duct systems, as well as equipment room space planning forethought and interdisciplinary coordination. The design intent shall be sufficiently documented, including explanation of provisions to facilitate projected future requirements.

Access panels shall be of appropriate size and type, and their locations shall be clearly noted in the design documents.

The arrangement of HVAC systems shall be coordinated with the arrangement of the laboratory planning modules so as to promote operational flexibility. Such planning should be documented so that the intended provisions may be understood and maintained). Thoughtful consideration of access restrictions and security issues are beneficial to minimizing impact on facility operations.

6.1.5. Systems Failure and Disaster Mitigation

Systems shall be designed and materials selected to minimize potential for loss of service and to limit impact on research and vivarium operations in the event of disaster or malfunction. Throughout the planning and design stages, the A/E shall evaluate each system to assess potential steps that may be taken to alleviate future damages, service disruptions, and promote rapid restoration of temporary and normal services.

Failures in HVAC systems can cause substantial impact to facility operations and loss of research. While many catastrophic utility failures can be prevented or controlled by provision of redundant equipment and appropriate standby power supplies, utilizing freeze protection measures, commissioning activities and BAS monitoring; these specific additional precautions should be addressed in the design of HVAC systems for research and vivarium along with an evaluation of additional risks in conjunction with the program. The rapid restoration of services and minimization of damage is critical in any emergency and is best accommodated through careful planning and installation quality control. Additional provisions may be found in the requirements for each system.

6.1.6. Energy Efficiency and Water Conservation: Systems shall be designed and equipment selected using best practices to achieve optimal energy efficiency and water conservation, without compromising the research program, safety, reliability, or the requirements within the NIH Design Requirements Manual, code, and referenced standards. Approaches must be cost-effective, durable, holistically considered, and present a reasonable payback (Follow federal guidelines such as EISA 2007).The project with a payback less than 10 to 15 years is highly favorable.

Energy and water conservation not only are federal mandates, but required of responsible design. Design approaches to achieve water and energy conservation must not be focused only on that goal, but must maintain the safe and reliable operations of the facility. Approaches must be cost-effective over the lifecycle of the facility and present a reasonable payback. Thoughtful consideration is required in reviewing sustainability approaches to ensure the solution is ultimately beneficial, energy-efficient, cost-effective, and does not otherwise compromise operations. The goal is not about just achieving “points” in a scoring system, but rather to utilize justified practices that provide holistic benefits.

6.1.7. Heating and Cooling Load Calculations

Complete heating and cooling load calculations and a vapor drive study (where applicable) shall be prepared for each spacewithin a design program and presented in a format similar to that outlined in the ASHRAE Handbook of Fundamentals. Heating and cooling load calculations are required for all projects to facilitate review and provide a reference for system modifications. Individual room calculations shall be generated and summarized on a system basis and presented with a block load to define the peak system load. Load summary sheets shall indicate: area of individual rooms, supply air quantity, L/s (cfm), ACH, and corresponding exhaust air quantity. Calculations shall include, but are not limited to: indoor and outdoor design parameters, heat gains and heat losses, supply and exhaust requirements for central systems, and for each area of the facility, humidification and dehumidification requirements, and heat recovery.

6.1.8. Laboratory Equipment Cooling Loads

1.The HVAC system shall provide, as a minimum, a cooling capacity for 1,892 W (6,455 BTUH) (sensible heat) for laboratory equipment in a typical 22 m2 (237 ft2) laboratory module (8 Watts per sqft) _or cooling for the actual calculated load, whichever is greater.

2.The A/E shall make a detailed and complete inventory of all laboratory equipment scheduled for installation in each space and determine the projected equipment load requirement using estimated diversity factors. The A/E should evaluate equipment nameplate ratings, heat release data and usage factors and overall diversity.

3.The detailed cooling load calculation including equipment diversity factors shall be indicated in the Basis of Design report.

4.The A/E shall evaluate the following rooms used for laboratory support, often having higher than normal cooling loads, as well as evaluating the use of supplemental cooling units to offset excessive sensible loads affecting these areas, while maintaining minimum ventilation requirements:

(a)Common equipment rooms

(b)Autoclave rooms

(c)“Clean” and “dirty” cage wash rooms

(d)Glassware washing rooms

(f)Special function rooms

(g)Electron microscope rooms

(h)Bio-Informatics/Robotics labs

(i)Labs associated with physics such as Lasers, Optics and nuclear material

The minimum 8W/sqft for equipment load may be used for generic labs and as a planning tool where all the equipment has not yet been specified. It is required that the A&E use actual equipment data for calculating actual loads Labs at NIH facilities have tended to be equipment intensive and prone to equipment creep as scientists add more table top equipment over time.

Due to lack of data on parameters such as nameplate data, heat release date and usagefactors, it is often difficult to analytically derive the equipment loads. As a result, designers typically assume the worst case for each of these parameters, thereby grossly overestimating the actual equipment loads. It is not recommended to use instantaneous peak load as the basis for calculating heat release. What is more important is average peak load. Generally space temperatures are not sensitive to instantaneous peaks of a few seconds and therefore it is unnecessary to size HVAC systems based on peak instantaneous power. It is rare for all equipment simultaneously and most equipment operates with duty cycles below nameplate ratings. The purpose of determining the actual equipment load data is to right size the HVAC equipment to lower initial construction cost as well as life cycle energy cost.

Information on some of the common equipment can be found in the ASHRAE Laboratory Design Guide. The Labs 21 benchmarking database also provides data on energy use and demand

If snorkel exhaust is used near equipment, the convective portion of the equipment can be discounted from the space cooling load. Also, heat from equipment that is directly vented or heat from water cooled equipment should not be considered part of the heat release into the room.

6.1.7.2. Animal Room Cooling Loads

The central HVAC system shall be able to remove both sensible and latent heat produced by laboratory animals. The total heat gain for animals is function of weight and the metabolic rate of each animal. Heat generation from animals for the purpose of HVAC load calculations shall be as listed in the ASHRAE ApplicationHandbook.

6.1.8. Animal Density

A typical 3 m (10 ft.) by 7 m (23 ft.) animal holding module shall be designed to the animal population density shown in Figure 1.

Figure 1. Design Density for Animal Populations

Design Animal Density
Species / Animals per Rack / Racks per Module / Animals per Module
Mouse / 300 / 5 / 1500
Rat / 90 / 5 / 450
Guinea pig / 40 / 5 / 200
Rabbit / 8 / 5 / 40
Cat / 8 / 5 / 40
Nonhuman primate / 8 / 5 / 40

Outdoor Design Conditions

6.1.7.1. Occupancy Loads

The A/E shall base HVAC load calculations on the expected occupancy in each space and the activity level as per ASHRAE Fundamentals Handbook.

6.1.10. Lighting Loads

Please refer to DRM electrical section and ASHRAE 90.1 for the lighting load requirements. The A/E shall base HVAC load calculations on actual lighting loads.

6.1.11. Outdoor Design Conditions

1.All facilities shall be designed in accordance with the climatic conditions listed in ASHRAE Handbook of Fundamentals. For summer conditions, use 0.4% column dry bulb(DB) / mean coincident wet bulb (WB) temperatures. For winter conditions, use 99.6% column DB temperature. Summer mean coincident wind speed (MCWS) shall be 0.4% DB column. Winter MCWS shall be 99.6% DB column. See Figure 3 for outdoor design conditions for Bethesda and Poolesville campuses.

2.Sizing of evaporative type cooling towers shall be based on 1°C (2°F) higher than the WB temperature shown in the 0.4% column (10a) shown in the ASHRAE Handbook of Fundamentals.

3.All approved outdoor air-cooled condensing equipmentfor Bethesda shall be designed and selected on the basis of 35°C (95°F) ambient temperature.

Figure 3. Outdoor Design Conditions (Bethesda)

Outdoor Design Conditions
Season / Temperature °C (°F) / Wind Speed m/s (mph)
Summer / 35.0 (95) DB, 25.6 (78) MCWB / 5.4 (12)
Winter / - 11.6 (11) DB / 4.8 (10)
Evaporative cooling / 26.7 (80) WB / n/a

door Design Conditions

6.1.12. Energy Conservation/Efficiency/Recovery

1.The A/E shall utilize the latest edition of the following energy codes and standards to design the exterior envelope for selecting HVAC and mechanical systems.

(a)ASHRAE Standard 90.1

(b)ASHRAE 189.1 (c)NFPA Standard 45

(d)ANSI Standard Z9.5

(e)International Energy Conservation Code

(f)All applicable federal mandates, executive orders, codes and standards for energy efficiency and sustainable design

2.Efforts to reduce energy must not compromise safety requirements required by NIH Division of Safety (NIH/DOHS).These systems must maintain the required environmental conditions at all times.

  1. Energy conservation measures must be both appropriate to NIH facility and have reasonable payback.
  1. For laboratories, it is encouraged to use variable volume control of exhaust air through fume hoods by reducing exhaust airflow when the fume hood sash is not open.
  1. It is encouraged to use room cooling hydronic HVAC systems such as chilled beams that decouple the room cooling function from the ventilation function and minimize reheat. .
  1. Due to mainly once through supply air systems in laboratories and animal research facilities, significant energy is lost as exhaust. A&E shall utilize energy recovery systems for energy conservation, but these should be balanced against risk of cross contamination from exhaust to supply stream. .The risk for potential cross-contamination of chemical and biological materials from exhaust air to intake air and potential for corrosion and fouling of devices located in the exhaust airstream should be evaluated.
  1. When evaluating energy recovery costs, all costs (pumping, air pressure drops, etc.) on both sides of the equation should be evaluated. It is recommended that some level of degradation due to fouling be included in the calculation.
  1. Run-around coils are used to recover sensible heat from exhaust air steam to the outside air stream, via coils, and glycol piping and pumps. There is no risk of cross contamination between exhaust and intake air. Combination heat recovery-preheat coils should be avoided due to complications in controlling and possibility of overheating intake air in summer time. Roughing filters shall be used upstream of exhaust coil serving animal facilities and corrosion protection should be applied in exhaust coils serving laboratories.
  1. Energy recovery heat recovery wheels recover total energy (sensible and latent) and are more efficient than sensible heat recovery systems. They require supply and exhaust ductwork configuration to be adjacent at the heat recovery device. There is potential for cross contamination from exhaust to supply. Exhaust from fume hoods and chemical storage rooms shall not be permitted to pass through heat wheel system. Energy recovery wheels are permitted in administrative buildings if purge and labyrinth sealing system are used tolimit cross contamination to 0.04% of the exhaust air concentration by volume. The transfer media shall be coated with 3 angstrom molecular sieve desiccant. Silica gel desiccants allow significant cross contamination from exhaust to supply streams and are not permitted. Energy recovery wheels for laboratory system shall be evaluated based on programmatic use of the building, the analysis of the hazardous materials and chemicals planned to be used in the building, requirement of factory and field performance testing to verify allowable cross contamination limits.
  1. It is encouraged to use actual laboratory equipment load data as described under 6.1.18 above for right sizing of equipment and improving energy efficiency.
  1. The Project Officer shall be notified (with justification) when requirements of the energy conservation codes and standards cannot be satisfied due to program requirements. New construction or major renovation shall require complete HVAC and energy simulation modeling. Life cycle cost shall include capital cost factors for chillers and boilers as provided by NIH, as well as up to date energy costs.

Airflow control for Variable Air Volume (VAV) hoods must be integrated with the laboratory control system and its setting and operation must not jeopardize the safety and function of the laboratory.