Control and prevention of Legionnaire’s Disease

Bacteria legionela

The most important factor in successfully preventing Legionnaire’s Disease is the design and correct maintenance of the cooling towers and water supply systems (above all, of domestic hot water) in order to reduce the growth and spread of the legionella bacteria.

The most effective way of preventing the growth of legionella is by means of adequate analysis, control and preventive treatment, so as to avoid the spread of the bacteria throughout the premises and installations, as stipulated in the Royal Decree RD 865/2003.

Our company guarantees a thorough control of this bacteria without disrupting the everyday activities of our customers’ premises.

Our goal is to control the bacteria in both high and low-risk premises according to the following guidelines:

  • Our highly-qualified staff make an initial visit to the premises in order to carry out a first-hand assessment of the possible risk factors and ascertain the critical points of each of these.
  • Preventive cleaning and disinfection processes aim to guarantee the optimum microbiological state of the water during the normal functioning of the premises. A specific, individualised maintenance programme is drawn up for all premises at risk, this including the recording and checking of all the maintenance operations to be carried out.
  • It should be noted that a thorough check of the correct functioning, excellent working condition and cleanliness of the premises will be carried out during each visit.
  • An overall inspection of the working order of the installation includes a thorough check of all its parts and of the water treatment systems employed.
  • An inspection of the general state of maintenance and cleanliness of the liquid reservoirs, cisterns, hot water tanks will be carried out in order to detect the presence of sediment, scale, corrosion, slurry or any other substance that might adversely affect the proper functioning of the installation.
  • Should rust or other forms of corrosion be detected, an adequate preventive treatment process will be drawn up so as to avoid the reappearance of such problems. In some cases, this will mean informing our customer of the need to replace certain parts of the equipment.
  • The physical, chemical and microbiological quality of the water system will be thoroughly checked.


1.1. A specific maintenance plan is drawn up and implemented for each installation at risk.

A plan for the prevention and control of Legionnaire’s Disease is drawn up, ascertaining the critical points and avoiding those ranges in temperature which favour the development of the bacteria. Subsequently, appropriate chemical products are used in each installation in order to clean and disinfect the area thoroughly.

  • Having assessed the hazardous areas, corrective and/or preventive measures are implemented by means of specific maintenance programmes individually designed for each installation in order to minimise the possibility of future outbreaks of the bacteria.
  • Specific treatment, maintenance and hygiene programmes are set up according to the type of installation in question, with the following objectives in mind:
    • Preventing the risk of the Legionella bacteria from proliferating and spreading.
    • Fulfilling all the current legal requirements.
    • Improving the building’s thermal performance.
    • Optimising the consumption of water and chemical products.

1.2. Analytical control of critical points

Our company works in close collaboration with a laboratory in order to meet our customers’ needs.

  • Physio-chemical and microbiological analyses.
  • Inspection and checking of the critical points of the premises.
  • Checking and callibration of various automatic chlorination systems.

Record of the maintenance works acording to Royal Decree RD 865/2003

  • A specific record book is maintained for each installation. The cleaning and disinfection protocol observed throughout the year, as well maintenance plans and records, are duly written down.
  • A certificate is issued for each cleaning and disinfection process carried out in all installations, specifying the protocol applied, dosis, duration of treatment and the operator who implemented the work.
  • Maintenance programmes are drawn up and implemented for the health and hygiene prevention of Legionnaire’s Disease in high-risk premises (cooling towers, evaporator condensors, domestic hot water systems, heated water systems in swimming-pools, spas, jacuzzis, whirlpools, etc.), as well as in low-risk installations (cold water networks, pipes, water tanks, cisterns, ornamental fountains, fire-sprinkler systems)


2.1. High-risk Legionnaire’s Disease Installations

  • Cooling towers and evaporator condensors.
  • Hot water systems with buffer storage tanks and return circuit systems.
  • Heated water systems with constant air bubble and water recirculation via high-speed jets and injection of air.
  • Industrial humidifier plants.

2.2. Low-risk Legionnaire’s Disease Installations

  • Internal cold water networks for human consumption.
  • Non-return circuit hot water systems.
  • Evaporative humidifiers.
  • Ornamental fountains.
  • Water reservoirs.
  • Fire-fighting sprinkler systems.
  • Car washes.
  • Sprinkler irrigation systems.