Hi Steve,

Good range of services.

What do you offer for the assessing of explosion hazards? How can you tell if process dust we are handling will be explosive or not?

-- So far the Plant Operators ask the question of the Project Engineers

-- The Insurers don't know, they only recommend fees chargeable and handle claims

-- The Mines Department doesn't know - it's too detailed for them

-- The Fire Department doesn't know - it's outside their usual training

-- The Plant Safety Department doesn't know, because nobody else knows

-- The Work-Safe guys say it's the Plant Managers job to assess it

-- The Plant Manager doesn't see why he should pay money to assess the risk levels. Ask the Consulting Engineer

-- The Consulting Engineer is no longer in business, or if he is all records of the basis for making decisions on explosion hazards have been archived and lost

-- The Risk Assessment Consultants say they will do it for a fee - come and interview your Operations staff and write it up as a Report

-- So the responsibility goes back the Operations Manager. He can't see any problem - nothing has exploded to date under his watch. So go back and ask the Plant Operators who raised the question in the first place

At the end of the day no one knows, and no one cares less. If in doubt pay for some explosion doors on your baghouses, and call it a high explosion hazard, even if everyone knows you are talking pure bullshit.

Is the dust explosion hazard assessment industry in your neck of the woods any more clued up? If so, how do you quantify the risk assessment level in real terms?

Please advise - Sgt John.Rz

www.latviantourists.com.au / Open Book Club / Files / Bionic Research Institute ■

Send Chilworth, or various other organisations, a sample of the dust to be handled. They will test the material, advise if it will explode if ignited with air, and advise the Kst value etc. measured from the tests.

The safety requirements of the handling and storage system can then be established. ■

What tests? Is there a Standard?

I tried a number of Testing Laboratories in Perth, West Australia. Most had never heard of such a thing. The CSIRO said it was difficult and would cost big bucks.

It doesn't seem to make sense to have to airfreight samples to UK from Australia - though it could be done. My problem was ignorance on site, ignorance in the industry, and tight control of the cash justification by the Operations Manager, and the accounts department. Nothing has exploded yet, so why spend $10,000 AUD on some tests no one else wants or demands.

To me it was a duty of care thing. If we ever ended up in an inquiry we had no test data to show we cared. ■

It's all here and well known in Europe. It must have made it's way down under.

http://www.chilworth.co.uk/services/explosions.aspx ■

Interesting post from John but you don't say what dust it is that you have...is it coal,stone,flour ?? also it is very fine dust or not?then perhaps someone could advise if it could be explosive. ■

Those who process/generate the dust must be able to provide the safety data to equipment manufacturers. This is done by testing whatever dust is being processed/generated. It's not hard or particularly expensive to test if a dust mixed with air will result in an explosive mixture.

Since dust explosions have the potential to destroy plant and injure/kill employees would you want to rely on what someone told you on an internet web site or the results of scientific testing? ■

Thanks designer,

The issue is not about getting instant solutions on the internet. The issue is that there is a lot of fuzzy thinking about in the industry.

As project engineers we are dictated to by Safety Managers who often seem to be on another planet. Their field of vision is at Plant-wide managerial level. And their assistants are keen young people who are still studying the basic text books [we are politely asked to help educate these youngsters to help them come up to speed. Some of them can't read a Process Flow Diagram. Many could not identify hazards from a General Arrangement drawing because such skills are not taught in their Hazard Awareness Seminars. The seminars focus on general procedures, not on specific technical details].

And when we ask for hard data on safety in a working plant environment they send us to a Hazop Seminar [some of them don't even know what the term means, or what is involved in the detailed analysis procedures. And they are certainly not going to allocate some of their budget to obscure technical tests that they don't understand or care too hoots about].

A standard catalogue of dust types is like trying to design a conveyor on the basis of CEMA charts - it is possible, but leaves a lot of blind spots with respect to flow properties and dust control. CEMA might give you one category for iron ore - but ores from different parts of the mine have different characteristics. The same is true of gold ore, copper, mineral "sands", and many other products handled by different plants.

The insurers don't care that much - just fit another blast panel, or fit a dozen water sprays. A lot of it is theory. When you have to design plant details it becomes a different story. Even control of explosive products of combustion in a protected substation can challenge the logic conflict between the Insurer's "good text book", and what the industry can deliver in response time and integrated safety controls.

In one case we were dealing with char. Is this char different to that char? Is it flamable, or not? What is its calorific value? Can you test it in a bomb-calorimeter to stop an argument between the naive ladies in the safety department, and the operating and maintenance staff who have worked with the stuff for decades? And not one - not even the Mine Manager - is willing to allocate any budget to testing the stuff, because our consultants want to come and do their Hazard Analysis interviews and guru procedures stuff to amaze us and charge rich fees.

Regards - Sgt John.Rz ■

I am only familiar with the EU and the requirements of ATEX 95 and 137 which are all about health and safety.

It is a requirement for employers to have full knowledge about anything that affects the health and safety for their employees, and this includes the explosive characteristics of dusts they handle, process or create. It is a legal requirement. This data is then to be made available to equipment suppliers to ensure that equipment supplied is safe when handling or processing the dusts, or just being in a dust environment.

So, in the EU it is legal requirement to have a safe workplace, and a legal requirement to supply safe equipment. Explosion hazards are just one part of this. The UK enforcement agency is the Health & Safety Executive. If you are involved in a dust explosion these are the people you will be up against and have to explain your actions to, or who may even prosecute you in court.

These links may be of assistance on ATEX

http://www.hse.gov.uk/fireandexplosion/atex.htm

http://ec.europa.eu/enterprise/atex/guide/index.htm

The initial test to check for an explosive dust is usually done in a Hartmann Tube. If this does not show that the dust is explosive then end of story.

Further tests on the explosive characteristics of dusts then establish the Kst value (indicating the intensity of an explosion), the maximum pressure rise, the maximum and minimum dust concentrations, the limiting oxygen concentration, the dust layer ignition temperature and the dust cloud ignition temperature.

This link describes the tests and corresponding standards

http://www.chilworth.com/labdust.cfm

(PS, I've no connection with this company)

Is this char different to that char?

In materials handling what's in a name?? It's well known that one man's "stuff" can be totally different to another man's "stuff" although the name is the same. Only the naive would assume (makes an ASS of U and ME) materials with the same name are the actually the same. To do a handling plant you'd want to see, and test maybe, the material. Same with dusts that may or may not be explosive.

Anyway, that's my take on it. ■

phenderson,

Are your doors and vents ATEX certified as protective devices for use in the EU? ■