Conteudo Principal


Apr 22, 2020

COVID-19: Preparing to open closed buildings  

EPAL recommends Good Hygiene Practices for Building Water Networks

During the exceptional measures implemented in the state of emergency, some buildings, floors and establishments temporarily ceased their activities. Some schools, companies, shopping centres, hotels, holiday apartments, shops, gyms, health clubs, clinics, restaurants, coffee and pastry shops, as well as other commercial and service activities are in this situation. 

On the resumption of their activity, it is essential to ensure that the quality of the water supplied by EPAL to the customer at the entrance to the building (service connection) does not undergo changes within the building network on its way to the taps. 

These changes can occur because the water is not moving and has been in contact with the building network pipes, booster units, tanks, welds and fittings, as well as due to the absence of a minimum level of free residual chlorine. Therefore, it is essential to ensure the maintenance of the home building network (hot and cold water) before the return to normality and opening of buildings, floors and establishments. 

EPAL has ensured the quality of the water treated and distributed in the city of Lisbon throughout the period of the pandemic through thousands of tests of physical-chemical, microbiological and organoleptic parameters being carried out on samples collected throughout the system, from the origins to the consumers’ taps. 

The maintenance of the home building network is the responsibility of the customer/owner, and they must ensure that the building system as a whole, consisting of pipes, taps and accessories (in the common areas and inside individual flats), is in good condition.

Good practices to be implemented 

Prior to the resumption of activity, in order to prevent changes in water quality and the proliferation of Legionella in building networks, particularly in large building systems, EPAL recommends the following preventive measures: 

1.  Clean/disinfect cold water (CW) and domestic hot water (DHW) tanks; 

2.  Discharge via discharge valves, installed at the end of hot and cold water networks, for a minimum of two minutes to force circulation in stagnant water points; 

3.  Refresh the water in the cold water network pipes, allowing it to run for a minimum of two minutes through all taps, including baths, showers and cisterns; 

4.  Clean taps and shower heads to remove accumulated debris, as indicated in the specific section of this brochure “How to disinfect taps and accessories”; 

5.  Maintain adequate levels of free residual chlorine in cold water networks (between 0.2 and 0.6 mg/L); 

6.  Ensure that the hot water tanks and/or water heaters are emptied (if possible) and, after filling, they should be kept at a temperature of 60°C for at least one hour before being put into operation in order to guarantee a minimum temperature of 50°C at the furthest point of the network or in the return pipes; 

7. Run hot water taps for about 5 minutes; 

8.  If the building/home network is old, the water may change colour due to contact with the building network materials, and you must let the water run on the first use of the day; 

9.  Clean filtration systems in the building network if they exist. If they do not allow self-cleaning, they must be disassembled in order to clean their interior; 

10.  Carry out control and monitoring of water quality (for example biocide residue, pH, hardness and, among others, alkalinity) according to the maintenance programmes that have been implemented; 

11.  Assess the need, in the case of shopping centres, hotels, gyms and health clubs, to screen for Legionella at critical points in the system; 

12.  Check and maintain protection devices in the building supply network in closed circuit systems (anti-pollution valves) if they exist and if necessary.

Attention: If you identify any more complex problem, we recommend contacting companies specialising in cleaning and disinfecting building networks

How to disinfect taps and accessories

Cleaning and Disinfecting Taps without Filters and Non-removable Shower Heads 

•  Clean the outside of the tap and the shower head with a suitable detergent;

•  Then disinfect the visible inner part with a cloth soaked in a solution of commercial bleach at 0.1% free residual chlorine or disinfect with 70% ethyl alcohol; 

•  Wait a few minutes and turn on the tap, letting the water run for a few seconds, thus eliminating the remaining disinfectant. 

Cleaning and Disinfecting Taps with Filters and Removable Shower Heads

•  In the case of a tap and shower head with filters inside, remove them and use a brush to remove any sediment; 

•  Place the filters in a container and let them stand for 30 minutes in a solution of commercial bleach at 0.1% free residual chlorine or in 70% ethyl alcohol; 

•  Complete the operation by replacing the filters. Turn on the tap and shower and let the water run for a few seconds to eliminate the remaining disinfectant; 

• Control and monitor water quality for residual biocide, pH, hardness, alkalinity, and, among others, Legionella.

More information here

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