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Flexible laboratory design and the demise of the fixed reagent dropper
As Wood Life Sciences Technical Director and an Australian Department of Agriculture, Forestry and Fisheries (DAFF) accredited Third Party Assessor, I've been asked this question a lot lately by end users, project managers and design consultants.
For over five decades, Wood Life Sciences has helped deliver some of the world’s largest and most complex pharmaceutical, biotechnology and research and development facilities. We approach every project with a problem-solving mindset, advising our clients on the best solutions to solve their unique challenges.
We’re always seeking new ways to design laboratories and facilities to achieve efficiencies and create a space to innovate. When it comes to lab air dispersion, we see most within industry using metal diffusers as a tried, tested and familiar solution. Whilst some engineering companies do install fabric ducts to Level 2 facilities, this alternative is not typically widespread.
The standards that govern Level 2 microbiological containment laboratories have key requirements around exposed surfaces being smooth, easy to clean and chemically resistant. These parameters are typically met with flush ceiling mounted metal face diffusers.
At Wood, we’ve been using fabric ducts as a preferred solution for laboratory air dispersion, transporting and diffusing it to create a good working environment with clean, quality air.
Why are fabric ducts suitable for PC2 / BSL2 laboratories?
PC2 / BSL2 labs are facilities certified as suitable for research or diagnostic practices on pathogens of Risk Group 2, low-risk dealings with genetically modified organisms and human cell cultures and body fluids.
As a result, this type of lab must contain the following features that minimise the risk of infection to individuals and the environment:
- Decontamination washbasins, eyewash equipment and heat-based decontamination equipment
- Open spaces under benches and equipment to inspect decontamination
- Fully enclosed space with smooth, impermeable by water, cleanable and damage resistant surfaces
- Dedicated air handling systems that ensure laboratory air is not recirculated into non-rated laboratories or non-laboratory spaces
PC2 / BSL2 facilities are designed with containment of aerosolised microorganisms at their very core. Primary containment is provided by biological safety cabinets, which act as the front line in protecting the user from airborne particles. Secondary containment is the build form of the laboratory aimed at containing accidental release of aerosolised micro-organisms.
These elements focus the requirements around being able to address contamination of surfaces by aerosolised particles and thus be able to not only clean them, but also effectively decontaminate them.
The secondary challenge is the impact of air distribution on the primary contaminant devices and the directional air movement through the greater space in the event of a spill.
Fabric ducts provide the perfect solution to assist these requirements. There are a variety of configurations and materials options in the market for fabric ducts which meet PC2 / BSL2 requirements. There are even antimicrobial and non-organic fabrics to aid compliance in this area.
What are the benefits of fabric ducts and why they should be considered?
The use of fabric ducts is often primarily driven by limitations in available space within ceiling voids and high air change rate requirements. That is, the fabric duct installed below ceiling level. However, the true benefit in my mind is not the space saving, but the significant improvement in air distribution.
Bench work, and primary safety devices such as fume cupboards and biological safety cabinets (BSCs) can all be adversely impacted by air jets and in some instances by the Coandă effect developed from certain ceiling mounted air diffuser types.
A fabric duct allows a high volume of air to be provided to a space in a very diffused manner at low velocity, which reduces the risk of impacting research equipment or safety devices. This makes fabric ducts an ideal candidate for spaces such as tissue culture due to the typically condensed size of these spaces and high density of BSCs which can make ceiling mounted air distribution very challenging.
Fabric ducts have several additional benefits beyond their superior air distribution characteristics. . They weigh less, are quick to install and highly durable. They also require fewer raw materials and are recyclable. Energy efficient, they can be adapted and contribute to quieter HVAC systems. By default, fabric ducts are also excellent filter of particulates in the supply air stream.
What are the key installation considerations?
There are key design coordination issues that need to be managed, particularly around ceiling devices (lighting, sprinklers, smoke detectors) as fabric ducts could interfere with the coverage of these devices. These challenges can be overcome with input from electrical and fire services engineers, while taking architectural visual aspects into consideration.
Connections to parent ductwork and ceiling details also present their own challenges. Focus is required on mount configurations as some surface configurations include channels that are difficult to clean. However, there are simpler contiguous fabric cross sections that address this. Additionally, mechanical system configuration approaches can ensure long term consistency in supply rate and space pressure consistency.
How we’re using fabric ducts in laboratory design projects at Wood
We’ve been using fabric ducts in the design and build of PC2 / BSL2 projects for decades. They are a highly suitable solution for quality air distribution and provide a lower cost, more sustainable and durable alternative to metal face diffusers.
Below is an image of a PC2 laboratory I helped design and deliver for an Australian education and research body, installed around 2011. This installation formed the exemplar and created a blueprint for a significant number of further installations on that campus. We are now using a version of this approach in some containment glasshouse applications.
So, can you install fabric ducts in PC2 and BSL2 laboratories?
Yes, you can install fabric ducts in PC2 / BSL2 laboratories. And they should be considered as a viable alternative to traditional ducting, based on the range of benefits they can bring to lab sustainability and efficiency.
Appropriately designed fabric duct installation can provide a lower embodied carbon footprint compared to galvanized ductwork and lower fan energy consumption which demands their inclusion in any sustainability assessment of the laboratory mechanical systems. With their low velocity air diffusion into occupied spaces, fabric ducts also provide improved acoustic performance and better comfort for laboratory staff.
