Improperly Functioning Lab Ventilation System

Importance of proper Lab Ventilation System
  • A fume hood can only function if it is a part of a lab HVAC system that supports its operation.
  • The Lab Ventilation System is a master that controls and determines the efficiency of the various ECDs.
  • The “safest” fume hoods cannot function if they don’t have adequate supply air.

What is Lab Ventilation System?

A Lab Ventilation System (LVS) is the primary system that is designed to limit the potential damage caused by airborne chemical hazards to lab users, the lab environment and experimental results. This is done by controlling the accumulation and movement of these airborne contaminants, thereby helping to deliver the highest possible Indoor Air Quality within the lab.

A properly designed lab ventilation system includes all exposure control devices like fume hoods, ventilated enclosures, spot extractors etc. and brings them together to deliver the safest conditions with optimal energy utilization.

Differential Pressure Shifts

A fume hood works on the principle of differential pressure. The hood must be negative as compared to the room and the room must be slightly negative as compared to the outside area. Differential pressure can only be balanced as such when there is real time coordination between the supply and exhaust.

Given the variable nature of hood and room exhaust and supply system, this differential pressure gradient shifts several times a day. Moreover, there is no direct communication between the exhaust and supply systems, so maintaining a real time balance becomes even more difficult. Even opening the door of the lab leads to a shift the differential pressure, which can lead to a loss of containment from the hood.

Why Lack of Supply Air in Labs is Dangerous?

Fume hoods are often viewed as standalone devices but in reality, they are a part of the complex LVS Fume Hoods are exhaust devices but, if the room HVAC doesn’t bring in the required amount of supply air, they won’t function as expected. When the HVAC System is designed, a specified amount of supply air is planned for the fume hood. But, in many cases, there is no direct communication between the fume hoods and LVS.

So the system may not really know, in real time, how much air the fume hood is exhausting. The system then struggles to regulate the desired volume of supply. The variance in supply air can create a situation wherein the fume hood cannot contain and exhaust the chemical contaminants that are present within the hood chamber.

These contaminants may then leak out of the fume hood and into the lab, leading to Loss of Containment.

In the likely event of the loss of containment, a lab ventilation is designed to ensure that the chemical fumes do not remain in the lab for an extended period. In the absence of an adequately designed LVS, these escaped contaminants settle on the furniture and fume hood surfaces, leading to the corrosion.

If treated and coated metal is corroding in these environments, the impact on the lungs of our users can only be imagined.

Fume hoods and other ECDs are complicated devices within the complex Lab Ventilation Systems. The systems are always in a state of flux, leading to continuous shifts in differential pressure.

If the LVS is not properly designed and operated, even the best ECDs cannot function as expected, leading to a major compromise in containment confidence. Thus, large sums of money are being spent to run systems that don’t really deliver the expected level of safety.