HVAC for laboratories: HVAC for laboratories:no room for error

By Ilana Koegelenberg

When designing and installing heating, ventilation and air-conditioning (HVAC) systems for laboratory applications, professionals need to stay up to speed with the latest standards to ensure they meet the stringent requirements of this industry.

There are generally two types of laboratories; for the production of pharmaceuticals and for diagnostic or research, explains Gregers Chalker of Air Filter Maintenance Services (AFMS). The first is generally kept at positive pressure (to keep the bad bugs out), while the latter has a negative pressure (to keep the bad bugs in – for example Ebola and tuberculosis). Both come with very rigid rules and regulations.

Why do you need HVAC?

HVAC is of the utmost importance in any laboratory environment.
Almero Oosthuizen, a mechanical engineer at Nako Triocon, shares the primary functions of HVAC systems in laboratories:

  • Personnel comfort: The HVAC system should ensure comfortable conditions for laboratory occupants.
  • Experimental quality: The HVAC system should ensure that the integrity of the experiments is maintained by controlling the temperature, humidity, and air quality.
  • Pressure relationships: The HVAC system is used to maintain proper pressure relationships between adjacent spaces in laboratories. This is to ensure directional airflow from ‘clean’ to ‘dirty’ spaces to protect personnel and experiments.
  • Personnel safety: The HVAC system provides outdoor air to laboratory spaces, which is a safety requirement for the personnel in the laboratories. Hazardous laboratories require more outdoor air than less hazardous laboratories.
  • Environmental protection: The HVAC system is used to filter contaminated air before the air can be discharged to the environment.

“In the South African context, one of the key requirements for an HVAC system within a laboratory would be related to thermal-comfort levels being maintained to establish recommended norms,” explains Danny Zdanow of ITD Group. While this will no doubt be one of the main user-requirement specifications (URS) issued by the end user, the primary objective would be to provide a safe, comfortable and productive environment for all the occupants using the facility.

“The possibilities of product contamination during testing, contagious biological contamination and hazardous external contamination should also be a consideration when designing the HVAC system for a laboratory,” says Zdanow.

 

Image credit: Ilana Koegelenberg

Temperature matters

Pharmaceutical laboratories are required to be 19°C to 23°C with less than 55% relative humidity (RH), explains Gary Miller of Aspen Pharmacare. This is according to Good Laboratory Practices (GLP); harmonised international regulatory bodies such as the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) and the Pharmaceutical Inspection Co-operation Scheme (PIC/S); and pharmacopoeia such as United States Pharmacopeia (USP), European Pharmacopoeia, the Medicines and Healthcare products Regulatory Agency (MHRA), and more.
These temperatures used to be ‘just a comfort-air requirement’, which has now been formalised, explains Miller. “There are potential risks caused by variable temperatures (whether higher or lower) and humidity affecting chromatographic/analytical test method retention times and interfering with the chemical and physical properties of chemical substances being weighed in small quantities and affecting substance dissolved in test solutions,” he says. However, note that different geographical zones (northern Europe for example), may have slightly different temperature ranges (18°C – 22°C).
“The most important considerations are efficiency, reliability, cost, maintenance, and environmental impact,”
says Miller.

Things to consider

HVAC in laboratories must meet specific, extremely stringent safety requirements since its purpose is to protect the people working in these labs, explains Matthias Olders of Trox. “In laboratories where hazardous substances are handled, the design of the HVAC system has to focus on the protection of staff and of the environment.”
When it comes to designing HVAC solutions for laboratory applications, there are several things to take into consideration.
According to Oosthuizen, consider the following:

  • The type of laboratory;
  • The operations carried out in the laboratory need to be understood;
  • The risk associated with the specific laboratories;
  • Room data sheets need to be provided for each unique area;
  • The exhaust and supply requirements and air quality requirements;
  • The heat load of the equipment and personnel;
  • The relative pressure requirements of the laboratories;
  • Special ventilation, flow, and directional flow requirements; and
  • All this information needs to be documented upfront and signed off by all parties.

Containment laboratories need HVAC to keep the samples being worked on inside the laboratory space and not possibly contaminating the adjacent spaces, Chalker elaborates. “The laboratory must be under a negative pressure, which is created by exhaust air fans in conjunction with high-containment filtration systems to filter all of the exhaust air.” As the space is under a negative pressure, there must be HVAC to replace the air exhausted, he explains.

For containment, you need to look at air-tight construction, risk assessments, what agent or pathogen is being diagnosed or researched, and will it or can it contaminate the environment or people, explains Chalker.
The extract air flow determines the required supply air flow, explains Olders. “The extract air quantity depends on the type and size of a laboratory and on the fume cupboards and other extraction equipment.” At night, a reduced air-change rate is sufficient.

Zdanow breaks requirements down into URS requirements and those for health and safety:

URS requirements:

  • Description of equipment and operating requirements;
  • Design criteria associated with either the product, equipment or personnel requirements;
  • Bio safety levels to be achieved;
  • Building design philosophy;
  • Cleanliness classification required in each area;
  • Building construction and finishes; and
  • Support facilities required.

Health and safety requirements:

  • Cooling/heating capacities;
  • Pressurisation requirements (positive or negative);
  • Energy consumption;
  • Contamination risk;
  • Separation of areas being served by air-handling equipment;
  • Need for once-through air-handling units with full fresh air, and dedicated exhaust unit;
  • Duct-manufacturing specifications and pressure-testing requirements;
  • Filtration standards;
  • Product exposure;
  • Product disposal recommendations; and
  • Decontamination procedures and facilities.

Standards and regulation

There are many standards and guidelines relevant to the design of HVAC systems for laboratories and it is important to comply with all of these. Each country typically has its own regulations for compliance according to the laws of the specific country.

The right system for the job

What HVAC systems are available and how do they compare?

Although the type of system will be determined by the application, chilled-water systems are generally more customisable to specific requirements and are generally preferable due to the typical special requirements of laboratories, explains Oosthuizen.

Miller confirms that Aspen predominantly uses chillers. “Price is the key differential, while support and maintenance are also important,” he explains.

And don’t forget humidity control. Total air conditioning is a requirement for laboratories and the tolerances on relative humidity are often within tight limits, explains Pieter Aldred of Humidair. This means that the temperature must be within very close tolerances. Even if element humidifiers are used, offering accurate control response, they need a continuous load to work against. This can be achieved by continuously dehumidifying or with fresh-air supply. “For temperature control, chilled water systems seem to give best results,” he says.

Looking at maintenance

Like with all HVAC systems, maintenance is very important. All systems contain components that require attention at regular intervals to maintain stable operation, explains Oosthuizen. For example:

Filters need to be cleaned and/ or replaced;

  • Fan belts require adjustment;
  • Sensors can drift or fail over time and need to be tested and replaced if necessary;
  • Wear and tear components need to be replaced as required, for example, motors, fan-belts, bearings, filters, heaters; and
  • Testing and validation of performance of systems relative to design parameter needs to be carried out at scheduled intervals.

“Maintenance is essential,” confirms Miller. This is prescribed by the International Society for Pharmaceutical Engineers (ISPE)’s HVAC Good Practices Guide Volume 2.

“Maintaining an installed plant to optimum levels of operation is one of the main areas of cost-saving potential available throughout the life of a plant,” says Zdanow. “However, maintenance is often one of the first operations that is sacrificed under a cost-saving review.

Decision making in these areas is often taken with little understanding of the possible immediate and long-term consequences that poor maintenance planning can have – especially in relation to significant unforeseen and unscheduled cost implications and seriously increased life-cycle costs, says Zdanow.

Listed below are some of the negative implications of a lack of maintenance planning, according to Zdanow:

  • Operating efficiencies and running costs can increase;
  • Equipment breakdowns, both minor and more serious, will occur more often, possibly resulting in product loss and unscheduled production downtime;
  • Life expectancy of systems and equipment will be significantly reduced; and
  • Risk of contamination exposure increases.

A word of advice

What are the dos and don’ts of laboratory HVAC system design?

“Do employ an experienced consulting-engineering firm with a known track record in laboratory design that has the necessary contextual experience and capability to know what you should and shouldn’t do,” advises Oosthuizen.

"Choose a practical location,” says Miller.

“You should not forget the importance of the supply air for the total performance of your laboratory space and HVAC system,” advises Older. “The supply air is crucial for the right performance.”
Some tips and tricks from Zdanow include:

  • Make sure that the required outcomes are fully understood before any planning takes place;
  • Review all design criteria to confirm conformance to URS;
  • Submit all manufacturers’ equipment data sheets and manufacturing layouts for approval before production work progresses;
  • Prepare relevant commissioning and validation documentation up-front and obtain compliance approvals;
  • Ensure that all critical programme dates that affect the HVAC progress are clearly defined in the main contract programme, and all delays are recorded;
  • Carry out ongoing progress inspections and pressure testing of ducting and piping, with documented records of all tests, whether successful or not;
  • Ensure that integrity-pressure testing is carried out by the party responsible for construction on all enclosed spaces within the building subjected to controlled pressure regimes before any air balancing proceeds;
  • Do not energise any plant or install any HEPA filters unless the building has been fully completed and all areas thoroughly cleaned; and
  • Document, document, document everything.

Energy savings

Energy savings is very important when designing HVAC systems for laboratories, explains Oosthuizen. “Systems need to be designed from the onset with energy efficiency in mind. This includes optimised design, such as energy-efficient motors, energy-recovery devices and taking care not to overdesign systems for the required needs.”
However, “it is sometimes necessary to waste energy to achieve a stable condition for effective humidification control, in other words, dehumidifying as well as simultaneously, humidifying,” explains Aldred.
“From a cost point of view, energy savings is very important,” confirms Miller.
"Do not skimp on the control system used to maintain conditions and consider the installation of a building management system (BMS) with capabilities for off-site monitoring, energy reporting and optimisation of plant operation,” says Zdanow.

Trends

Zdanow has noticed these trends:

  • Automatic control of airflow balancing between areas using phoenix valves, providing accurate and sophisticated control of pressure regimes required within the facility without manual intervention; and
  • The increasing usage of woven fabric ducting to distribute the supply air, reducing the possible risk of air drafts that can affect sensitive measuring equipment.

According to Oosthuizen, flexible laboratory spaces are the latest trend in laboratory architecture. It is highly beneficial to design the HVAC systems to be easily adaptable to differing requirements of airflow, air exchange, and so on. “Also, displacement air type systems are in the process of being tested in practice with varying degrees of success,” he says.

10 tips

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