Posted By Richard McLellan
my company currently classifies wet abrasive blasting as cold work. However those who work with the equipment say that some companies classify wet abrasive blasting as spark potential.
Blasting operators certainly report seeing sparks in the water jet while blasting, but whether these have the potential to be an ignition source for a gas/air mixture is another question. If they can, then of course the hazard should be reclassified. Much of our work is carried out in hazardous environment on oil/gas plant. I suspect the evidence for spark potential is anecdotal, following observed sparks - some hard science would be better.
I would like to see the scientific evidence on whether wet abrasive blasting can create a spark capable of being an ignition source.

Posted By Richard McLellan
Paul,
I must have expressed myself badly. Your question appears to be the same as my question, but put more succinctly. i.e. can wet blasting sparks be a source of ignition?

Posted By Richard McLellan
Paul,
I have posted this question internally in my company and to equipment manufacturers. I have recieved lots of opinion, all of which agrees with my belief that there is no risk of ignition from wet abrasive blasting. But still no hard science! There is a rumour that Rigblast did come experiments about 5 years ago and concluded there was no risk. I doubt if I will get a research based answer from this forum. If I do get one from my other researches, I will let you know.
Richard

Posted By Laurie
If there is a spark being produced, and in my opinion that is a very big if, then it is a potential source of ignition and must be risk assessed as such

Laurie

Posted By Stuart Nagle
Richard

it is a well known fact that some processes create elctro-static discharge, caused by the friction of the material in contact with the equipment employed in the process.

This is true of both dry and wet processes (e.g. vacuuming materials from drums into a process or mixture and high pressure water jetting), and would therefore assume that wet abrasive blasting, employing high pressure water jetting with an abrasive substance would indeed produce a risk of electro-static discharge.

In an atmosphere that is potentially flammable/expolsive (e.g. just the right amounts of oxygen and flammable gases/fumes etc - know as being within the explosive limit) such a discharge can indeed cause an explosion/flashover etc with serious results. (for example see Associated Octel case - although the cause of flashover was spark from bulb in atmosphere that was within exposive limit the end result exemplifies the fact).

An HSE Research report on electro static discharge may be of interest. it can located at the following web address - http://www.hse.gov.uk/re...otopdf/1995/oto95026.pdf

Regards...

Stuart Nagle

Posted By Stuart Nagle
Richard.

I would suspect that the fines used in the process would not be a cause of ignition source themselves, but would add to the potential of the equipment for statis discharge, by creating a higher level of static through contact in the equipment.

There are several BS EN standards on static electricy and earthing of equipment to help prevent static discharge. the numbers and descriptions can be obtained by logging onto the BS web site and doing a search (you can use a search engine to locate).

Regards...

Stuart