Anyone involved in the supply of water systems (e.g. designers, manufacturers, importers or suppliers of water systems) has duties under health and safety legislation. They must, as far as reasonably practicable, ensure that the equipment is designed, constructed and operationally functional; ensuring that it is safe when used at work and enables safe and easy operation, monitoring, cleaning and maintenance.

The Approved Code of Practice & Guidance: Legionnaires’ disease (L8) applies to the control of legionella bacteria in any undertaking involving a work activity and to premises controlled in connection with a trade, business or other undertaking where water is used or stored and where there is a means of creating and transmitting water droplets which may be inhaled, thereby causing a reasonably foreseeable risk of exposure to legionella bacteria.

A reasonably foreseeable risk of exposure to legionella bacteria exists in all water systems where the cold water is likely to exceed 20°C; the hot water system return temperature is not maintained above 50°C and they may release a spray or aerosol during use or when being maintained. A suitable and sufficient risk assessment is required to identify and assess the risk of exposure to legionella bacteria.

Note: The landlord, employer or self-employed, where there is a risk from their undertaking or premises, should appoint a ‘responsible person’ (Director or Manager status) to take responsibility for controlling any identified risk from legionella bacteria: ensuring all operational procedures are carried out in a timely and effective manner.

The responsibility of manufacturers, importers, suppliers, designers and installers is clearly described in L8 and when providing water systems it should be remembered that L8 also describes how all parts of the water system should be considered; which includes all plant/equipment and components associated within that system, e.g. all associated, pipe-work, pumps, feed tanks, valves, showers, heat exchangers, quench tanks, chillers, etc.

L8 requires whoever designs, manufactures, imports, supplies or manages water systems should, so far as is reasonably practicable:

• ensure that the water system is designed, constructed and maintained so that it will be safe and without risks to health when in operation;
• provide adequate information for the user about the operation, risk assessments and maintenance measures necessary to ensure that the water systems will be safe and without risks to health when used;
• inform the responsible person of new information made available about changes of the water system or its components and any risks to health and safety, enabling them to take appropriate action and update drawings and records of the water systems.

Suppliers of products and services, including consultancy and water treatment services, aimed at preventing or controlling the risk of exposure to legionella bacteria, should, so far as is reasonably practicable:

• ensure that any limitations on their expertise or on the products or services they offer are clearly defined and made known to the responsible person;
• ensure that any deficiencies or limitations which they identify in the occupier's systems or written scheme to control the risk of exposure to legionella bacteria are made known to the responsible person.
• ensure that measures intended to control the risk of exposure to legionella bacteria are so designed, installed and maintained that they will be effective, safe and without risks to health of those who use, or are exposed to and maintain the water system;
• ensure that their staff have the necessary ability, experience, instruction, information, training and resources to carry out their tasks competently and safely.

Water systems and their operation by their nature are regularly changed to meet the requirements of the operation. It is essential that accurate drawings records and component information are provided at installation and commissioning or alteration assisting the responsible person meet their statutory duty.

Article by:
Bill Harley
Principal Healthcare Engineer
Atkins Global