infection control
high degree of flexibility capable of accommodating structural movement.
Concrete tanks Unprotected concrete tanks are prone to erosion as they consist of micro- pores and if these are interconnected they can cause a build-up of moisture and pollutants. Once the process starts, exposed
aggregate can become more prominent, providing a potential breeding ground for micro-aquatic bacteria. And, under load, concrete will also
crack, providing further access points for bacteria to breed. Concrete tanks can, however, be
refurbished and relined. Any spalled area would be repaired
Protecting water tanks from bacterial growth
Water storage tanks are vital to support round-the-clock services, but can be a breeding ground for potentially-harmful bacteria. In this article, Mark Lemon of
CSC Services examines the challenges and advises on how they can be effectively protected
W
hy do water tanks corrode? Corrosion is the deterioration of a material that results from
a chemical or electrochemical reaction with its environment. Most water tanks are made of steel, a
material highly susceptible to corrosion, which is accelerated by various factors,
including the tank’s interaction with interconnected components, corrosive environmental conditions, and stray electric currents. Without implementation of appropriate
corrosion-control measures, water storage tanks will deteriorate, resulting in holes or possible structural failure. This deterioration will lead to micro
aquatic bacterial growth including Legionella, Pseudomonas and a build- up of biofilm.
Controlling micro-aquatic bacteria The best way to avoid micro-aquatic bacterial growth is to line steel water tanks with a solvent-free coating such as polyurethane, which has been approved by the Drinking Water Inspectorate (DWI). In addition to resisting the growth of bacteria such as Legionella, this offers a
46
healthcaredm.co.uk
and a cementitious coating – various products are approved by the BWI – applied to protect against water ingress and erosion. Cementitious coatings are also used
as sealer coats on the damaged concrete to fill out blow holes or voids in the surface of the concrete, and in some cases to fill out the concrete, returning it back to its original profile before a protective coating is applied. A DWI-approved polyurethane
coating would then be applied over this, providing full protection to the tank against erosion and micro-aquatic bacteria.
GRP Water tanks GRP tanks are common across healthcare estates, most often used where access is restricted or if replacement of a defective water tank involves structural alterations to a building. Even relatively-new tanks that are
regularly cleaned and chlorinated can present problems as many have cavities and cracks which often cannot be seen by the naked eye. If water osmotic blisters are evident
the tank should be examined immediately as, if these burst, their contaminated toxic contents can be released into potable water.
Effective maintenance I cannot express enough the importance of having the correct protective lining installed, from the commissioning of a new tank, to protect against bacterial growth from the outset. And, once installed, protective
coatings should be regularly inspected so that continuous levels of reliability and performance are maintained. Looking after tanks and ensuring the
right maintenance programme is in place is vital as small problems can quickly develop into major issues.
www.csc-services.co.uk
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61
