Good afternoon

I am a new HSE Lead and have inherited a combustile bead blaster room, the blast media is plastic particles.  There is a metal trough where the additional media is collected into, the current process is using a metal scoop to collect the media to then place into the ensloced unit.  The metal scoop doesnt seem right in terms of risk of sparks.

Should I be ordering a plastic scoop or is there a problem woith plastic and metal scrapping together?  Also is there a specific ESD requirement for brush and dustpan??

Thanks

Rather than having the world speculate might I suggest contacting the supplier of the media and/or unit and discussing your concerns with them. Their technical literature will provide guidance for use.

Plastic blasting pellets are likely to be quite resistant to ignition (unlike for example a fine dispersal of flour dust) so it would be unlikely a spark from a metal scoop would initiate an explosion, however you failed to advise what the media is intended to remove.

Hi Lorraine

There is of course a difference between "combustible" and "explosible" and a spectrum of each term.

Like Roundtuit I rather doubt that this material  is likely to be as "explosible" as the scenario first reads UNLESS the beads get ground together to produce dust.

So, you need more information about the nature of the material - from supplier, which then allows a proper "DSEAR" assessment to be carried out by a suitable team - and may be that will say you haven't got much of a problem.

.....or that assessment says you DO have a problem. Then time to work out what precautions to take and simply putting an extraction system might not necessarily be part of the solution.

Strictly you should get the dust tested for its explosive properties - there are designated standards which a material test lab will test to. However that doesn't mean your process in practice will lead to an explosive situation. You could look on the Gestis database for further information about your dust.

As well as having explosive properties the other factor to consider is the dust paricle size. Dusts larger than 0.5mm in size are not explosive - British Standard BS60079-10-2 Explosive dust atmospheres has a cut off at 0.5mm particle size.

Thats does NOT mean the dusts aren't combustible - which should be considered under your normal fire risk assessment.

For a dust /process to be explosive that ALL 5 criteria below must be satisfied at the same time

- the dust is explosive

- the must have a particle size that will explode

- the dust is at an explosive concentration in air

- the air has sufficient oxygen concentration

- there must be an ignition source present

As a rule of thumb guide, for a dust cloud to be explosive, the concentration will be such that it will be difficult to see through the dust cloud. A dust cloud explosive concentration is typically quoted as 20-30g/m^3

For comparision occupational health exposure limits are down around the mg level

Ref Dust Explosion Prevention and Protection A Practical Guide - John Barton ISBN 0852954107

Any further DSEAR questions, drop me a message, DSEAR is what I do.

Hi Lorraine

A PS to what John has written.

Devastating dust explosions rarely happen due to the initial combustion but rather where that creates a pressure wave that disturbs the potentially explosible dust that has settled on surfaces - these are then ignited in a "secondary dust explosion".

So, one of the various things which should be done is to house processes which generate explosible dust is to design buildings etc to minimise the existence of any ledges on which dust can settle.

Which still leaves floors and the flat or flattish surfaces of equipment - so then consideration of extraction to capture what is emitted and/or a very high standard of cleaning.

Don't forget to record all you have learned from this thread on your CPD record!!

REPORTED hyperling after the introduction of the quote NadiaEira

Originally Posted by: Roundtuit

REPORTED hyperling after the introduction of the quote NadiaEira

Drift Hunters

Prioritize safety by ordering a plastic scoop for handling plastic bead media to minimize the risk of sparks.

drewbinsky REPORTED