Thermal insulation for pipes

Legionnaires’ disease is an underreported and severe form of pneumonia transmitted by pathogens in water. There is no reliable epidemiological data for the disease in Europe, but estimates vary between 10,000 and 20,000 cases per year. Contaminated air-conditioners, swimming pools or whirlpools and cooling towers are well-known sources of infection. Errors made in the design and installation of sanitary systems can also lead to a dangerous rise in legionella in drinking water as well as fountains, sprinkler systems and humidifiers for food display cabinets. Therefore, one of the most important preventative measures is to insulate both hot and cold water pipes using suitable materials.

Legionella are bacteria which can get into the drinking water systems of large buildings such as hotels and hospitals through the central water supply. They are particularly likely to multiply in stagnant water at temperatures between 25 and 45°C. The bacteria become hazardous when they are inhaled as small droplets (e.g. as aerosols when taking a shower). People who are chronically ill or have a weak immune system are at particular risk of contracting Legionnaires’ lung disease, which may be fatal. Because the symptoms are similar to those of flu, the condition is often not diagnosed correctly, with an estimated 95% of cases going unrecognised.

A combination of measures are available to prevent microbial contamination. These include a number of operational, constructional and process-related measures to avoid a harmful multiplication of legionella in drinking water and, where possible, a combination of these should be implemented. Apart from ensuring that the water circulates continuously through the pipework, it is also necessary to prevent unacceptable temperature decreases in hot water pipes and increases in cold water pipes. According to the European standard BS EN 806-2, pipes for cold drinking water should not follow the same routes or run adjacent to space heating or hot water pipes. Cold water pipes should be protected against heat gain by ensuring sufficient clearance or preferably by insulating properly. Similar requirements apply for hot water pipes to protect them against heat loss.

When hot and cold pipes are laid in one duct or wall cavity, or wherever water is not circulated regularly, Armacell recommends using what is known as 100% insulation, i.e. an insulation thickness which roughly corresponds to the pipework outer diameter. On hot drinking water pipes this not only prevents legionella, but protects pipes against unnecessary energy losses. On cold water pipes the insulation provides protection against freezing in cold weather, as well as protecting against unwanted temperature rises.

Armacell insulation materials including AF/Armaflex Class O, Armaflex Tuffcoat and Tubolit protect pipes against temperature increases and decreases. Due to their efficient technical properties, these insulation materials reliably prevent the temperature fluctuations in pipework and at the same time protect the installations against energy losses. The closed-cell material structure also prevents moisture ingress and corrosion of pipework.