Title:

Emergency Drop-down Exhaust

Hazard Category:

Chemical

Hazard(s):

This case study presents an engineering solution to a potential hazard at the Birck Nanotechnology Center at Purdue University. The hazard is chemical vapor exposure due to an unwanted chemical release.

Problem:

A chemical spill or release can pose an immediate health risk for workers.
The area of the hazard could spread rapidly if the vapors are not contained.

Risk Description:

Vapors from the chemicals can enter the body through various pathways (respired, ingested, dermally absorbed, etc.).
For examplle, HCl vapor, in high concentration, can be corrosive to human tissue.
It is important to know the properties and effects of the chemicals and how to contain them in case of a spill.

PtD Strategy

Prevention through Design is the effort by design engineers to make safer workplaces through implementing safety at the project design stage. PtD strategies used with the emergency drop-down exhaust system at the Birck Nanotechnology Center include:

Used locally to eliminate unwanted gases from spreading within the subfab.
Creates negative pressure that acts as a vacuum to pull in free vapors or fumes and sends them through the normal exhaust system.
Can be positioned at any level above the hazardous area to keep vapors or fumes away from breathing zones.
Easy pull chain engagement and storage back into ceiling tube.

Method of operating the system:

In case of a localized gas emergency, pull overhead chain.
Yellow tube will drop from ceiling and can be guided to the hazard area.
The “vacuum” will pull in harmful gas that may be respired by personnel.
When decontamination is complete the tube is fed back up into ceiling housing with the use of a ladder.

Images

This is a photo of the emergency drop-down exhaust system.

The next photo is a demonstration of how a worker would begin to deploy the drop-down exhaust in a simulated event using the bottle on the floor as an example of a chemical spill.