This article looks at the signs that a critical ventilation system is malfunctioning, and why it’s important to get it checked as soon as possible. One way of avoiding any problems is to have a regular maintenance contract with a qualified team of engineer, which Tecomak Environmental Services can provide. 

This article is a four-minute read.

Critical ventilation systems are appropriately named because they are essential in healthcare and specialised environments to prevent the spread of airborne infections, maintain sterile conditions, and protect vulnerable patients and staff from contaminants.

While they are used primarily in hospitals and healthcare environments, they can also be present in pharmaceutical production facilities and scientific research labs, where any issues with the air quality could compromise the product or put years of research at risk.

So any problems with the critical ventilation system could have far-reaching consequences, which is why it is essential to look out for any signs that it is not performing as it should. Here Tecomak Environmental Services have listed five of the most common tell-tale signs.

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1. Visible “Fogging” or Lingering Contaminants

In a high-performance environment, air should clear rapidly. If you notice steam, dust, or chemical vapours lingering in the air longer than usual, the Air Change Rate has probably dropped. This is likely to be due to malfunctioning or clogged filters (either HEPA or carbon), which are restricting the airflow.

Room air change rates should be at least 75% of the original design. While the 75% efficiency figure reduces energy usage, it also lowers the rate of, and efficiency in, removing contaminants or controlling the environment, meaning the air in the room is not being replaced as fast as originally planned.

2. Unexplained Pressure Shifts

Critical ventilation systems rely on pressure differentials – positive pressure to keep contaminants out, or negative pressure to keep them in. If doors are suddenly easier or harder to open, the seal is not being maintained and there may be a leak in the building envelope.

Sometimes the pressure sensors monitoring the room may be providing inaccurate data, leading to the system either over- or under-reacting. Equally, the air filters could be clogged or damaged. This can severely restrict airflow, altering the resistance and pressure balance. It could also be a mechanical problem, as worn belts can also disrupt the airflow.

3. Increased Noise or Unusual Vibrations

While ventilation is never silent, a change in the usual noises that a critical ventilation system makes should act as a major warning sign.

If there is a whistling noise, there could be a leak in the ductwork, or a problem with one of the seals. A grinding or rumbling sound is more likely to be a mechanical failure, possibly in the fan bearings or drive belts.

These should be investigated immediately. A failing fan, for instance, can lead to a total system shutdown without warning.

4. Physical Symptoms Among Your Personnel

If any members of your staff are reporting headaches, dizziness, watery eyes, or think they can smell pungent chemicals, then the chances are your critical ventilation system is failing to capture hazardous substances at source.

Specifically, it may show that there are problems with the face velocity of your fume cupboard or fume hood – that is, the speed at which air is drawn into its open face. In the UK, most specifications aim for a face velocity of 0.5 m/s across the sash opening.

It may also be the result of dampness in the system (clogged ducts can lead to mould growth) or malfunctioning filters, which are allowing internal or external pollutants to circulate.

5. Inconsistent Temperature or Humidity Control

Critical ventilation isn’t just about moving air, it involves conditioning it as well. If a room feels “stuffy” or humidity levels are rising, the AHU (Air Handling Unit) is probably struggling to do its job properly.

Sometimes the system may be working effectively, but it is too big for the area it is covering.  An oversized system may cool the space too quickly and shut off before it has run long enough to effectively remove any moisture (dehumidification), resulting in low temperatures and high, fluctuating humidity.

Temperature problems may also be caused by dirty or clogged filters, while the humidity can be adversely affected by problems with any refrigerants or evaporator coils the system uses.

In laboratories, high humidity can ruin sensitive samples or cause microbial growth within the ductwork itself. Temperature variations can also cause issues for products, processes and for staff, as in point four.

Critical Ventilation Services from Tecomak

So any illnesses, unexplained noises, or problems with the humidity or should be a cause for concern and a reason to call in qualified professionals such as Tecomak Environmental Services.

We can design, install, commission, maintain, and validate critical ventilation systems for hospitals, laboratories, and high-risk environments. If any of your systems show any of the above signs, we should be able to fix them. For more information call us on 01732 852250 or click here and fill in the online form.

FAQS:

Q: What is the legislation surrounding critical ventilation systems?

A: The most important legislation is HTM 03-01. This Health Technical Memorandum says that all such systems should be verified at least annually, and ideally more frequently than that. Checks should involve a number of detailed measurements, including to air volumes and air change rates, room pressure differentials, and to diffusers and pressure stabilisers. The key elements required for HTM 03-01 verification can be found here.

The COSHH (Control of Substances Hazardous to Health) regulations from 2002 also apply; these are designed primarily to protect patients, staff and operators.

Q: When was HTM 03-01 last updated?

A: The last update was in 2021; it made some changes, both in terms of how systems should be designed depending on the type of healthcare location it serves, and to the types of risks posed by infectious diseases, one year on from Covid-19. For more information see our previous article here.

Q: Does Tecomak offer maintenance contracts for such systems?

A: Yes – we can schedule regular inspections, or we can deal with one-off problems as and when they arise. We will always try to fix any issues on the spot.