SC20 - Appendix 3
06 Dec 2010



Guidance for Completing a DSEAR Risk Assessment


​The STFC Risk Assessment Forms located within STFC SHE Code No 6 (Appendix 5a and Appendix 5b) should be used to record the finding of the explosion risk assessments and hazardous area classification. The table below provides guidance on what might be included in each section for an assessment where DSEAR is a consideration.

Step Title Notes
1 What are the Hazards? Note the specific explosion hazards by identifying the dangerous substances in use and whether the manner in which they are used could give rise to a flammable atmosphere either inside equipment items or within the workplace area.

Note whether hazardous area zones need to be applied again either in equipment items or in the surrounding workplace. And define what these will be and how far they will extend.

If the formation of a flammable atmosphere is very unlikely then positively state this and define the area or equipment item as non-hazardous.

Note the credible ignition sources that may come into contact with the flammable atmosphere and if they are sufficiently energetic to cause ignition (i.e. low energy static discharges may not ignite most dusts). Limit the ignition sources to those that could credibly be present in that instance rather than listing every possible single ignition source imaginable.

2 Who might be Harmed and How?

Identify groups of people. Remember:

  1. some workers have particular needs;
  2. people who may not be in the workplace all the time;
  3. members of the public;
  4. if you share your workplace think about how your work affects others present.

Say how the hazard could cause harm e.g. explosion in small vessel in fume cupboard may cause vessel to rupture but unlikely to cause serious injury to personnel in the laboratory.

Record how you think harm can be caused to affected people. Will they suffer contact burns; consider if clothing will be ignited or provide protection. Will there be poor or oxygen limited combustion that will produce harmful levels of carbon monoxide causing intoxication. Will oxygen levels be depleted so as to cause asphyxiation. If an explosion is predicted will the person suffer primary harm (blown over, damage to lungs or ears etc) or secondary effects (falling from height etc.) Will affected people retain sufficient faculties to make a safe exit; for example ammonia releases quickly attacks eyes and lungs affecting judgement and functioning.

3 What are you already doing? List what is already in place to prevent or mitigate the effects of an explosion; record if the control is preventative or mitigating. Include hazardous area classification and correct equipment for the zones if applicable.

Are you complying with the good practice examples where applicable?​

4 What further action is necessary? You should decide if the residual risks of an explosion at this point are TIFALARP, and positively state the Basis of Safety as defined in Appendix 2.1 (PDF - 472kB - link opens in a new window)|.

If there is a difference between your control measures and best practice, list what needs to be done to achieve a viable Basis of Safety.

5 How will you put the assessment into action? Remember to prioritize. Deal with those explosion hazards that are 'high risk' and have serious consequences first.
Contact: Baker, Gareth (STFC,DL,COO)