Waterproofing Drinking Water Reservoirs

Drinking water is a precious resource. It needs to be kept clean. Facilities to store drinking water must be watertight, have long service lives, and be easy to maintain. Coatings used to protect drinking water reservoirs must fulfill stringent hygienic, quality, exposure, and production standards, to avoid leaching from surface-applied waterproofing into water. Surfaces must be of smooth appearance to allow for easy cleaning. They must not affect drinking water quality and comply with the strict regulations of public water authorities. Essential requirements, pertaining to the protection of surfaces from infection, their resistance to attack from condensate and leaching, waterproofing properties, the sealing of blowholes, and the smooth-easy cleaning of surfaces, must be met. Facilities must withstand a variety of influences. They must be resistant to the chlorine treatment required to disinfect the water, the low pH value of the water, and to micro-organisms, algae, and fungi that influence water hygiene. Membranes must be elastic to avoid cracks caused by temperature differences and their bonding strong enough to avoid hydrostatic pressure and washout effects from circulating water.

Concrete tanks build to store drinking water should include an integral rigid waterproofing solution which includes high range water-reducers and pore-blocking active crystallization agents, sealing tapes for movements and construction joints**, and sealants** to seal construction and expansion joints. Additives based on pozzolanic silica fume are also used to reduce the hardened pore volume of the concrete.

Cement-based systems have a long track record from the hygienic, ecological and economic points of view. Holderchem offers a range of Vandex cement-based products approved for use for drinking product reservoirs, which include the following:

• Surface hardening agents based on silicates.
• Repair, and sprayable or brushable mortars with hydrophobic properties, which create a long-lasting durable, uniform, and continuous totally waterproofing membrane characterized by high strength and strong bonding.
• Sanitary self-levelling coatings.
• Specialty products.

For additional information pertaining to approvals and tests secured by Vandex, consult the Vandex drinking water brochure.