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Mandate Consultants help your company comply with Pressure System Safety Regulations

These notes are re-produced here by Mandate Systems Ltd – Pressure System Safety Consultants and are taken from the HSE website at http://www.hse.gov.uk

 

Pressure Systems - Safety and You

 

INTRODUCTION

 

This leaflet advises you as an employer, or a self-employed person (called 'users' and 'owners' in the regulations) on how to minimise the risks when working with systems or equipment that contain a fluid or gas under pressure. It does not cover work with gas cylinders (now called transportable pressure receptacles), or tanks and tank containers.

Equipment and systems containing a fluid or gas under pressure can cause death, or injury, to people if the contents are released unintentionally. They can also cause serious damage to property. Each year in Great Britain, there are about 150 dangerous occurrences involving such unintentional releases. Around six of these result in fatal or serious injury.

 

Examples of pressure systems and equipment are:

 

·         boilers and steam heating systems;

·         process plant and piping;

·         air compressor sets (fixed and portable);

·         pressure cookers, autoclaves and retorts;

·         heat exchangers and refrigeration plant;

·         valves, steam traps and filters;

·         pipework and hoses;

·         pressure gauges and level indicators.

 

Principal causes of incidents are:

 

·         poor equipment and/or system design;

·         poor maintenance of equipment;

·         an unsafe system of work;

·         operator error, poor training/supervision;

·         bad installation;

·         inadequate repairs or modifications.

 

The main hazards are:

 

·         impact from the blast of an explosion or & release of compressed gas or fluid;

·         impact from parts of equipment that fail or any & flying debris, such as glass;

·         contact with the released gas or fluid, such as & steam or chemicals;

·         fire resulting from the escape of flammable & liquids.

 

REDUCE THE RISK OF FAILURE

 

The risk from failure of pressure systems and equipment is dependent on a number of factors, which include:

 

·         the type of fluid or gas and its properties;

·         the suitability of the equipment and pipework & that contains it;

·         the age and condition of the equipment;

·         the complexity and control of its operation;

·         the skills and knowledge of the people who & design, manufacture, install, maintain, test and operate the pressure equipment and systems.

 

To reduce the risks you need to know, and act on, some basic precautions. Many are requirements under the Pressure Systems and Transportable Gas Containers (PSTGC) Regulations 1989 - the main regulations covering pressure systems and equipment.

 

Provide safe and suitable equipment

  • If installing new equipment, ensure that it is suitable for its intended purpose and that it is installed correctly. This requirement can normally be met by using the appropriate design, construction and installation Standards and/or Codes of Practice.

  • The pressure system should be designed and manufactured from suitable materials.

  • Ensure the system can be operated safely - for example, without having to climb or struggle gaps in pipework or structures.

Know the operating conditions

  • Know what fluid or gas is being contained, stored or processed (eg is it toxic/flammable?).

  • Know the process conditions - such as the pressures and temperatures.

  • Know the safe operating limits of the system and any equipment directly linked to (or affected by) it.

  • Ensure there is a set of operating instructions for all of the equipment and for the control of the whole system (including emergencies).

  • Ensure that appropriate employees have access to these instructions, and are properly trained in the operation and use of the equipment or system (see the section on training).

Fit suitable protective devices and ensure they function properly

  • Ensure suitable protective devices are fitted to the vessels, or pipework (eg pressure relief valves, fire relief valves, pressure switches, temperature switches and level switches).

  • Make sure the protective devices have been adjusted to the correct settings.

  • Make sure that, where fitted, relief valves discharge to a safe place.

  • If warning devices are fitted, ensure they are noticeable, either by sight or sound.

  • Make sure protective devices are kept in good working order - at all times.

Carry out suitable maintenance

  • All pressure equipment and systems should be properly maintained. There should be a maintenance programme for the system as a whole. It should take into account the system and equipment age, the environment and its use.

  • Look for tell-tale sign of problems with the system, eg if a relief valve repeatedly discharges at the wrong setting, this could be an indication that the system is not working properly.

  • Look for signs of wear and corrosion.

  • Where protective devices have to be isolated for maintenance, make alternative arrangements to ensure safety levels are not exceeded without detection.

  • Ensure there is a safe system of work, so that maintenance work is carried out properly and under suitable supervision.

Make provision for appropriate training

 

Everybody operating, installing, maintaining, repairing, inspecting and testing pressure equipment should be provided with suitable training, and have the necessary skills and knowledge to carry out their job safely. This includes all new employees, who should have initial training and be supervised closely.

Additional training or re-training may be required if:

  • the job changes;

  • the equipment or operation changes;

  • skills have not been used for a while.

Have the equipment examined

 

A written scheme of examination (WSE) is required for most pressure systems, for example:

  • if the system has at least one pressure vessel, containing a relevant fluid (eg compressed air) and operates at a pressure of 0.5 bar above atmospheric (and if the product of the pressure times volume is greater 250 bar-litres); or

  • if the system contains steam.

The key steps are:

  • Decide what items of equipment and parts of the plant should be included in the scheme. This must include all protective devices. It should also include pressure vessels, and/or parts of pipework that could give rise to danger, if they were to fail.

  • The scheme will need to be drawn up or certified as suitable by a competent person. It must specify the nature of the examination and how often the system is to be examined.

  • The system will need to be examined by a competent person in accordance with that scheme.

Choose a competent person

 

You must assure yourself that the competent person has the necessary knowledge, experience and independence to undertake the functions required of them.

The competent person carrying out examinations under a written scheme does not necessarily need to be the same one who prepares or certifies the scheme as suitable.

 

A competent person may be:

  • a company's own in-house inspection department;

  • an individual person (eg a self-employed person);

  • an organisation providing independent inspection services.

One competent person has to take responsibility for all examinations of a pressure system. For example, on systems where ancillary examination techniques (eg non- destructive testing) are undertaken by another person, the competent person must assume responsibility for the results of these tests and their interpretation.

 

Further advice

 

Professional advice is available from the following:

 

Your local HSE office - the number can be obtained from directory enquiries or the phone book - under Health and Safety Executive.

For premises covered by the local authority, eg offices and shops contact the Local Authority Unit enquiry point - Tel: 0171 717 6442 Fax: 0171 717 6418.

 

Related guidance and further information

 

This leaflet can tell you only a few of the main facts about the dangers associated with pressure equipment, and about your responsibilities under the Pressure Systems and Transportable Gas Container Regulations. Further practical advice is available as follows:

 

Safety of pressure systems Pressure Systems and Transportable Gas Containers Regulations 1989 Approved Code of Practice COP37 HSE Books 1990 ISBN 0 11 885514 X

Guide to the Pressure Systems and Transportable Gas Container Regulations 1989 HSR30 HSE Books 1990 ISBN 0 7176 0489 6

Written schemes of examination INDG178 HSE Books 1994

This leaflet is available in priced packs of 20 from HSE Books, ISBN 0 7176 1452 2. Single free copies are also available from HSE Books.

HSE priced and free publications are available by mail order from

HSE Books, PO Box 1999, Sudbury, Suffolk CO10 6FS.
Tel: 01787 881165 Fax: 01787 313995.

 

HSE priced publications are also available from good booksellers. For other enquiries ring HSE's InfoLine Tel: 0541 545500,
or write to HSE's Information Centre, Broad Lane, Sheffield S3 7HQ.

 

This publication may be freely reproduced, except for advertising, endorsement or commercial purposes. The information is current at 11/97. Please acknowledge the source as HSE.