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Technical Q&A

IIRSM members have free and unlimited access to three helplines as part of their membership; a technical helpline, a HR helpline and a legal helpline.   These helplines provide quick responses by phone or email to everyday queries, such as the application of health and safety legislation, staff issues and professional and person legal issues.  Every month we publish a selection of questions and answers from the technical helpline in our Member magazine, Insight.  Below are some recent examples which you may find interesting and informative.

Q. I am carrying out a fire risk assessment for a hotel. Where can I find information on calculating the travel distance to exits?


BS 9999:2017 Code of practice for fire safety in the design, management and use of buildings gives recommendations and guidance to achieve reasonable standards of fire safety for all people in and around them. In addition, the government’s Fire safety law and guidance documents for business are available at

Q. What statutory inspections are airlines used in vehicle workshops to inflate tyres subject to (specific regulation and inspection/test frequency)? We also use mobile air compressors to power pneumatic tools.


With regard to the both types of equipment the first question to consider is whether the airlines and air compressors would meet the definition of a pressure system under the Pressure Systems Safety Regulations. The following information taken from the guidance accompanying regulation 2 may be useful:

“The Regulations define three types of system: (a) a system comprising a pressure vessel its associated pipework and protective devices. There must be a pressure vessel in the system for the Regulations to apply under this definition. Where there is more than one system on the premises whether interconnected or not the user/owner is responsible for deciding where the boundaries for each system occur; (b) pipework with its protective devices to which a transportable pressure receptacle is or is intended to be connected. A transportable pressure receptacle on its own is not a pressure system as defined. Pipework containing a relevant fluid (other than steam) at a pressure of 0.5 bar or less is outside the scope of the regulations; (c) a pipeline with its protective devices.”  

For the purposes of these regulations a pressure vessel is a vessel used or intended to be used to contain a relevant fluid.

Therefore, the key point is whether the system contain a pressure storage vessel; if it does not then these regulations will not apply. However, if the system does contain a pressure vessel then the second question is whether the vessel contains a relevant fluid. The following information (also taken from the guidance) accompanying regulation 2 may be useful:   

“The following conditions have to be fulfilled for a fluid to be a relevant fluid within the scope of the Regulations: (a) the pressure must be greater than 0.5 bar above atmospheric (except for steam). Where the pressure varies with time the maximum pressure that is normally reached should be the determining factor; (b) either the fluid should be a gas or mixture of gases under the actual conditions in that part of the system or a liquid which would turn into a gas if system failure occurred.”


Therefore, the regulations will cover compressed air (a mixture of gases) as well as other compressed gases such as nitrogen acetylene and oxygen. The definition will also include hot water contained above its boiling point at atmospheric pressure (pressurised hot water) or aqueous solutions where a vapour pressure above 0.5 bar (gauge) is generated. Classifications of gases are given in BS EN 720-1:1999.    Only those parts of a system which contain a relevant fluid fall within the scope of the regulations except protective devices which are within scope irrespective of whether they contain a relevant fluid provided that they form part of a system which contains or is liable to contain a relevant fluid.


Except in the case of steam once the pressure along a line of pipework drops below 0.5 bar (gauge) there is no longer a relevant fluid and that part of the pipework is then no longer part of the system covered by the Regulations. For the definition of relevant fluid not to apply the user/owner should be able to show clear evidence that the system does not contain (and is not liable to contain) a relevant fluid under foreseeable operating conditions.    Therefore, if the gas in the pressure vessel is held at a pressure less than 0.5 bar above atmospheric then again these regulations will not apply. However even if the system does contain a pressure vessel and this does store a gas at a pressure of more than 0.5 bar above atmospheric then unless the pressure vessel has a pressure times volume product of 250 bar litres or more the requirements of regulations 8 (Written scheme of examination) and 9 (Examination in accordance with the written scheme) will not apply.   

Both the quoted information referred to above and further information on this topic can be found within the HSE publication Safety of Pressure Systems (available at

If the Pressure Systems Safety Regulations do not apply – or if they do but the requirement for a written schemes of examination will not – then the system will need to be inspected in accordance with the more general requirements of regulation 6 of the Provision and Use of Work Equipment Regulations.

Further information can be found in the HSE’s Safe Use of Work Equipment (

Q. I have been asked to carry out an inspection of a large, vacant, basement carpark. The site has been broken into on a number of occasions – can you provide guidance on the main hazards and control measures that need to be considered?


We haven’t been able to find any guidance specifically relating to these circumstances; it is likely that the main hazards will depend on the nature of the work that the people accessing the basement car park will be carrying out and the relevant risk assessments should help identify these.   

Examples may include from asbestos if the work will disturb the fabric of the building; from electricity or contact with dangerous parts of machinery etc. depending on the nature of plant being inspected; from legionella if the work will affect the hot and cold water systems etc.

Other more general hazards may include falls from height if the work requires the use of ladders, platform, etc; to work at height, manual handling for equipment or materials used for the work.

Q. What is the recommended number of Intermediate Bulk Containers (IBCs) that can be stacked when empty? We currently stack them four high, is this acceptable?


There is nothing specific within legislation, but HSG51: Storage of Flammable liquids in containers would be a good start. Although the information refers to full containers, it may still be of interest to you. The guidance says containers should be stored in a manner that facilitates safe handling. Where you intend to stack the containers you should check with the supplier that the containers are suitable for stacking and any limitations as to stack size. Stacks should be stable to allow for any leaking container to be readily spotted and be arranged in such manner to enable such a container to be easily removed. Except where a suitably designed racking system is provided, for practical operational purposes the limit for metal drums of nominal size (200 litres) stacked vertically will be three-high; horizontally (‘on the roll’) four-high. It is generally recommended that filled intermediate bulk containers (IBCs) are stacked no more than two high and then only when they are designed to stack together and ground conditions are suitable. See for more information.

Therefore, it’s probably best to speak to the supplier/manufacturer of your IBCs for advice on stacking and whether there are any restrictions.  

Q. I need to put together some food sample testing criteria (for example microbiological agent contaminants). This is for a typical office food supply sampling and testing purposes – can you provide any information or recommend resources?


The Food Standards Agency (FSA) has many sources of guidance to assist with food safety. The Food Law Code of Practice (Chapter 8 – Sampling and analysis) is available at

Food sampling resources can be found here: and more information for business and industry is at

Q. My organisation is considering converting one of our large offices into a crèche so our employees can bring their babies and toddlers to work. What would be required from a health and safety perspective?


There isn’t anything specific within health and safety legislation regarding turning an office into a crèche. The Health and Safety at Work Act requires employers to take appropriate steps to ensure the health and safety of their employees and others who may be affected by their activities when at work. You should also consider your emergency procedures, for example fire evacuation, first aid, bomb threats, etc.   

There are specific duties in relation to children under other legislation which might be applicable in this case for those working/looking after children.   

You may also wish to contact your insurance company as they may have restrictions on children in the workplace.  

The following websites may be useful:;; and