Sensor For Zinc Plating Fumes

I would approach one or more companies that produce gas-detecting instruments for such places as mines and confined spaces. Some that come to mind include Bacharach, Beckmann, Drager, Ex-tech, Manning, and MSA (Mine Safety Appliances). If they don't have what you need, they might still offer good referrals.

A zinc plating fume sensor will work.

Now really, if your company is so desperate to save a few pennies that they would spend money to vary the speed of a safety exhaust fan, I'd quit.

How long will it take to recover the cost of the sensor/VFD speed controller/installation/maintenance and replacement as needed of the whole speed controller system?

The costs probably won't be recovered before it fails and kills someone.

Bad idea!

A sensor is not required unless the fan speed is to be varied continuously. It is possible to vary the fan speed without feedback by using the manual function of the drive, possibly putting upper and lower limits in the parameters.

Before doing any of this, though, it is best to do a cost-benefit analysis to obtain a buy-in for the proposal. It starts by writing a short statement, say no more than 500 words, as to why the current situation is unacceptable and what needs to be done to improve it. Then publish it internally so as to obtain buy-in.

It's time to look at the issue from a helicopter, so to speak, rather than on the ground.

Thank you for all your excellent replies.

I think the ventilation exceeds requirements because we can switch it off for about 15 minutes before you can smell the fumes.

Also, we only work 12 hours per day, 5 days per week. In my opinion the ventilation could be reduced during the off hours.

I fully understand all the safety aspects raised - safety comes first.

The sensor required is the one that indicates that the fan is off which should trigger an evacuation alarm. The sensor needs to sense movement of the fan.

Switching off the fan is not permitted.

Running slower than needed to exhaust all the fumes should be indicated by a secondary alarm.

Switching off the fan is not permitted.

A process evaluation will tell you what the require exhaust flow rate is. Ask the process engineer.

From earlier posts you are the electrical engineer which should not alone decide about critical safety equipment.

Switching off the fan is not permitted.

Unless

The zinc plating line is idle or at halt.

You shouldn't rely on the sensing of fumes to control the extractor; if you have to save on energy consumption, consult with EHS about using an OMRON 24/7 timer.

Adapt a Fume Hood Monitor sensitive to Zinc fumes.

http://www.phoenixcontrols.com/en-US/solutions/Documents/FHMX30%20(MKT-0044).pdf

It will take some modifications to do it but isn't that one of the many tasks for engineers.

Good Luck, Old Salt