Control Schemes

A written scheme of control for Legionella is a comprehensive Legionella risk management document that clearly identifies those measures required to control the risks from exposure to Legionella bacteria, and how those measures are implemented and managed so that control over water systems is achieved and remains effective.

The written control scheme forms an essential risk management document that should be developed as a practical tool to be used by all parties involved in the Legionella control process.

The written scheme is separate to the Legionella risk assessment and is a legal requirement identified by the Health & Safety Executive in their Approved Code of Practice and guidance ACoP L8 / HSG274 “Legionnaires’ disease. The control of legionella bacteria in water systems”.

If a risk is identified which cannot be prevented, you must introduce proper controls. Risks from legionella in water systems can be controlled but careful planning, a successful management policy, competent staff and attention to proper control strategies are all essential in preparing a written scheme which sets out how you intend to control the risk from legionella.

The scheme should describe:

  • The system – to include an up-to-date plan or schematic diagrams are sufficient;
  • Who is responsible for carrying out the assessment and managing its implementation;
  • The safe and correct operation of the system;
  • What control methods and other precautions will be used; and
  • What checks will be carried out on the control scheme and how often.

The scheme should:

  • Ensure that the release of water spray is properly controlled;
  • Avoid water temperatures and conditions that favour the growth of legionella and other micro-organisms;
  • Ensure water cannot stagnate anywhere in the system by keeping pipe lengths as short as possible or by removing redundant pipework;
  • Avoid materials that encourage the growth of Legionella;
  • Keep the system and the water in it clean; and
  • Treat water to either kill Legionella (and other micro-organisms) or limit their ability to grow.

Waterman Environmental Services written schemes of control are developed and implemented utilising the following legislation, codes of practice and guidance

  • Health & Safety Executive: Approved Code of Practice and guidance (ACOP) L8 “Legionnaires’ disease. The control of legionella bacteria in water systems”
  • Health & Safety Executive: HSG274 Legionnaires’ disease: Technical guidance Part 1:
  • The control of legionella bacteria in evaporative cooling systems
  • Health & Safety Executive: HSG274 Legionnaires’ disease: Technical guidance Part 2:
  • The control of legionella bacteria in hot and cold water systems
  • Health & Safety Executive: HSG274 Legionnaires’ disease: Technical guidance Part 3:
  • The control of legionella bacteria in other risk systems
  • Department of Health: Health Technical Memorandum (HTM) 04-01: The control of Legionella, hygiene, “safe” hot water, cold water and drinking water systems Part A: Design, installation and testing
  • Department of Health: Health Technical Memorandum (HTM) 04-01: The control of Legionella, hygiene, “safe” hot water, cold water and drinking water systems Part B: Operational management
  • Department of Health: Health Technical Memorandum (HTM) 01-05: Decontamination in primary care dental practices
  • BS 8580:2010 “Water quality – Guide to risk assessments for Legionella control”
  • BS 7592:2008 “Sampling for Legionella bacteria in water systems. Code of practice”

For further information on how Waterman Environmental Services can produce a written scheme of control please contact us to speak to one of our specialists