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safetybod  
#1 Posted : 21 October 2019 12:20:53(UTC)
Rank: Forum user
safetybod

If there is ammonia on site (used for the purposes of refrigeration) is there a reuirement for a DSEAR assessment to be completed? Refcom make reference to a DSEAR assessment may be  required but cant seem to get a definitive answer from anyone. Thanks in advance

Ian Bell2  
#2 Posted : 21 October 2019 12:31:03(UTC)
Rank: Super forum user
Ian Bell2

I have done DSEAR assessments on ammonia refirgeration plant.

Ammonia is indeed a flammable gas, LEL 15% - however if you get a serious leak you will be long dead from its toxic properties before it catches fire.

If you haven't done one already, you might want to do an occupied building risk assessment - looking at toxic gas refuges, fitness of buildings. Also how far a toxic cloud may disperse/drift, it is likely to be several 100m and effect people off site if you have an ammonia tank/volume of ammonia on site to leak. 

thanks 2 users thanked Ian Bell2 for this useful post.
mihai_qa on 21/10/2019(UTC), A Kurdziel on 23/10/2019(UTC)
stevedm  
#3 Posted : 24 October 2019 18:11:06(UTC)
Rank: Super forum user
stevedm

You are not the only one around that can do or has done them...

You may find this useful but in answer to your question YES a DSEAR risk assessment is required...

http://bfff.co.uk/wp-content/uploads/2015/12/06_Maurice-Young_DSEAR_16052017.pdf

It is unlikely that the requirement for an Occupaied Buildings risk assessment would apply if you are only using an Ammonia refrigeration system...it is really only for COMAH level (schedule 1) inventories..

Ian Bell2  
#4 Posted : 24 October 2019 20:48:56(UTC)
Rank: Super forum user
Ian Bell2

I disagree entirely with the view that you don't need an occupied building risk assessment. if the ammonia receiver vessel. For even a moderate size factory you could have a few tonnes of ammonia in the refigeration system, which if you have a gross failure, lead to a toxic cloud over 150-200m quite easily.

Therefore site personnel need a toxic refuge where they can seek shelter in a short period ot time, without attempting to risk escaping by distance.

stevedm  
#5 Posted : 25 October 2019 07:50:27(UTC)
Rank: Super forum user
stevedm

I didn't say you didn't need it but it is unlikely that the HSE requirement for that will apply as it is for COMAH ...check out the specific industry links...high hazard sites do indeed need it however...a small ammonia system will need the appropriate risk assessment...

You will get more work by explaining the differences than lanching into scarcompliance.. this system could be anything from 1 small cylinder to what you describe...

Ian Bell2  
#6 Posted : 25 October 2019 10:58:14(UTC)
Rank: Super forum user
Ian Bell2

Its nothing to do with COMAH compliance and the trigger levels that COMAH has in terms of quantities of hazardous materials.

The point is, an ammonia refigeration system in anything like a modest factory environment producing bulk frozen foods, it is necessary to know what the consequences of a major ammonia leak would be - how bad, safety/dispersion distances, numbers of people at risk etc. That would come under your CoSHH assessment,

John Elder  
#7 Posted : 25 October 2019 15:12:40(UTC)
Rank: Forum user
John Elder

A DSEAR Assessment should take into acount sources of release such as the follow:

Normal Operation

Situation when the equipment is operating with its designed parameters

Rare Malfunctions

Type of malfunction which may happen only in rare instances

Note: Rare malfunctions in the context of the above include failure of separate and independent process controls, that may be either automated or manual, that could trigger a chain of events that would lead to major release of flammable substance. Rare malfunctions could also include

Un-anticipated conditions that are not covered by the plant design such as unexpected corrosion that results in a release.

Reasonably Foreseeable Misuse

Use of a product, process or service in a way which is not intended by the supplier, but which may result from readily predictable human behaviour.

It should have to cover the following unless it is for a COMAH Site Assessment

Catastrophic Failure

An occurrence which exceeds the design parameters of the process plant and control system resulting in a release of flammable substances.

Note: Catastrophic failures in the context of the above include, for example, major accidents such as the rupture of a process vessel, or largescale failures of equipment or piping such as total breakdown of a flange or seal

Therefore a standard DSEAR assessment should be appropriate.

 

Ian Bell2  
#8 Posted : 25 October 2019 23:13:35(UTC)
Rank: Super forum user
Ian Bell2

Toxicity is much more of an issue, than DSEAR

stevedm  
#9 Posted : 27 October 2019 08:41:15(UTC)
Rank: Super forum user
stevedm

Originally Posted by: Ian Bell2 Go to Quoted Post

Its nothing to do with COMAH compliance and the trigger levels that COMAH has in terms of quantities of hazardous materials.

The point is, an ammonia refigeration system in anything like a modest factory environment producing bulk frozen foods, it is necessary to know what the consequences of a major ammonia leak would be - how bad, safety/dispersion distances, numbers of people at risk etc. That would come under your CoSHH assessment,


DOH...then don't quote OBRA is required when it is just an approrpiate risk assessment...
Ian Bell2  
#10 Posted : 27 October 2019 17:13:52(UTC)
Rank: Super forum user
Ian Bell2

So how are you completing your CoSHH assessment if you don't fully evaluate accident consequences and emergency procedures/facilities that you might require in the event of a major ammonia leak?

More to chemical safety than COMAH.

John Elder  
#11 Posted : 28 October 2019 07:53:21(UTC)
Rank: Forum user
John Elder

Ladies & Gents

As usual I see with certain persons on this fourm  the Authors Thread and original question has been hijacked and taken off on a tangent.

The question asked was do i need to do a DSEAR Assessment.

Nothing was mentioned about COSHH or Toxicity or COMAH even if that is a greater risk they may have already knew that and know the answer and that is why it was not the question asked.

Instead off a contest to see who knows best, why not answer "only" the question asked, as i am sure outerwise that the Author would have asked for any other factors relevant they needed to consider.

thanks 1 user thanked John Elder for this useful post.
A Kurdziel on 28/10/2019(UTC)
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