Rank: Forum user 
|
Hello, New clients site has tonnes of waste lime dust coating everything. The MSDS rightly identifies the respitory health risk of the dust, and touches on the chemical reaction when wet, but there is no mention of any explosive risk. I remember seeing the Imperial Sugar explosion video; where the build up of powdered sugar on surfaces and fine particles in the air exploded. (14 dead, 40 injured) The scenes at Imperial look almost exactly the same as this current site, just with a different dust material. Is there a similar risk from other fine particle dusts such as Kiln lime dust (Calcium Oxide): MSDS states non-combustable so I think not but was wondering if there is a resource of knowing what dusts have this explosive risk. Is there a valid reason for not extracting this waste dust? It covers everything and everyone. Vaccuumed around the conveyers daily but still everywhere!
Thanks
|
|
|
|
|
|
Rank: Super forum user 
|
A dust can only be combustible if it is chemically able to react with oxygen. Calcium oxide is fully oxidised to start with so cannot take up any further oxygen and is completely non-combustible. Most kinds of organic material (sugar, flour) are able to react with oxygen whereas many minerals are fully oxidised and cannot react with oxygen. However the chemical composition of the powder is not all there is to whether it may create a dust explosion risk. The particle size distribution (how fine the dust is) is also important. So you cannot go on the chemical composition alone (unless it is fully oxidised in which case you can rule it out). In your case I would be very bothered about breathing it in, but not at all worried about dust explosion as this is chemically impossible. Edited by user 17 February 2022 14:08:32(UTC)
| Reason: Added conclusion
|
|
|
|
|
|
Rank: Forum user
|
Originally Posted by: Kate  Most kinds of organic material (sugar, flour) are able to react with oxygen whereas many minerals are fully oxidised and cannot react with oxygen.
Great, thanks for this, that's very helpful, I didn't know the science behind it so that's a simple way to understand it. So just the respitory, eyes and chemical burns risks then. Thanks
|
|
|
|
|
|
Rank: Super forum user 
|
If you can't find information from a reptutable source about a particular dust e.g. Gestis database you might have to send a sample of the dust off to a materials testing lab. They will test your sampe for its cloud ignition temperature, layer ignition tmperature, its ST rating, Pmax and Kst values.. This will then give you the information that you require to decide if a dust is explosive.
|
 1 user thanked Ian Bell2 for this useful post.
|
|
|
|
Rank: Super forum user
|
Self and Hasty Kate has dealt with the lack of explosion risk. But you also asked: "Is there a valid reason for not extracting this waste dust? It covers everything and everyone. Vaccuumed around the conveyers daily but still everywhere!"
Probably not. That it is settling on all the surfaces is indicative that you probably have a lot of inhalable/respirable dust being breathed in by the workforce. P
|
|
|
|
|
|
Rank: Super forum user 
|
FYI. Not only organic dusts can be explosive, but Aluminium dust can also be explosive for instance. Chris
|
|
|
|
|
|
Rank: Super forum user
|
|
|
|
|
|
|
Rank: Super forum user
|
Yes, dust itself is hazardous in fact ANY dust can be classed a hazardous substance if it is present at levels above 10 mg.m-3, as a time-weighted average over an 8-hour period, of inhalable dust, or 4 mg.m-3, as a time-weighted average over an 8-hour period of respirable dust; EH40 will tell what the WEL are for specific dusts. The presence of this dust suggest that the dust is not being capture by what ever systems are in use. What you need to do is: - to measure the dust levels and worker exposure levels
- identify the sources of the dust
- identify methods to capture the dust eg some sort LEV perhaps
- identify a system to maintain the system including testing
- identify a method to safely remove the dust eg sweeping it up is not a good idea and if you are going to use a vacuum cleaner then it will need a filter to capture the dust
- and maybe look at some basic health surveillance to see if the dust is creating any health effects
|
1 user thanked A Kurdziel for this useful post.
|
|
|
|
Rank: Super forum user
|
Thanks for A Kurdziel guidance on the Occ Health requirements. it should be noted that EH40 occ health limits are far stricter thn the explosive properties of dusts. Mots dusts don't explode until a concentration of 30-60g/m^3. At that concentration a dust cloud will be very obvious and most likely difficult to see through.
|
|
|
|
|
|
Rank: Super forum user
|
Ian, agreed but with a word of warning for those who might be reading this thread and be unfamiliar with the concepts. It's rarely the primary dust explosion that is devastating but the secondary explosion caused by the first lifting whatever has collected on surfaces. Hence the Imperial Sugar incident referred to by the OP but many, many comparable events. So, the OP has right to be concerned about accumulations on surfaces (even if the material in question is not combustible). That said usually the occupational health risks are much greater in most scenarios. Both need to be managed effectively. P
|
1 user thanked peter gotch for this useful post.
|
|
|
|
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.