WHY ARE FLEXIBLE MEMBRANE LINER SYSTEMS A SUPERIOR WAY TO STORE POTABLE WATER?
NSF 61 Flexible membrane liners are AWWA approved to store potable water. In structures and earthen ponds.
Black Carbon Steel Water Tanks — Either Welded or Bolted. Factory Powder Coated or Field Coating is required to protect the black carbon steel from rusting and pre-corrosion. They are generally coated with 5-7 mils of approved NSF61 powder or liquid coating on the interior and 3-4 mils on the exterior.
Flexible Membrane liners are used at times to elongate the lifespan of a bolted steel tank.
Corrugated Bolted Steel Tanks are made from Carbon Steel as well, they are Zinc Galvanized to ensure protection of the steel. This process adheres the galvanization to the steel through heat.
Therefore, an additional factory epoxy or powder coating is not required to protect the steel from moisture or corrosion. The tank is built to meet all structural codes through ASCE7-10 to hold water. However, the tank structure is not water tight alone. The factory welded, flexible membrane liner system acts as a massive sealant holding the water inside of the structure. The liner is NSF61 potable water rated to hold potable water safely. It also acts as a barrier between the galvanized steel wall and the water it is holding. Water does not sit up against the powder coating, mastic, sealant or galvanized bolts as it would in a Factory Coated Bolted Steel Tank (AWWA D103-09). The steel is further protected by a minimum of a 30-mil thick flexible membrane liner.
This elongates the lifespan of the tank.
Flexible Membrane liners are:
• Easy to install
• Inexpensive to replace
• Simple to repair
• Many options– some more cost effective than others
• Flexible membrane liners have long warranties up to 30 years– WARRANTY
• The 8 ox geotextile pre-liner is installed between the flexible membrane liner and the wall and floor of the tank. It is designed to protect the liner from the wall and the wall panel galvanization from friction damage. Much like a wet dry t shirt material works, it wicks water away that may have dripped down from interior condensation.
• Due to the protection of a Flexible Membrane Liner system, most Corrugated Bolted Steel Tanks are warranted for 10+ years.