Mesa Roof Drain systems ensure the proper drainage of water from the floating roof of Aboveground Storage Tanks (AST). Floating roofs are sloped towards a drain sump normally located in the center of the roof. One end of Mesa's flexible pipe assembly is connected to the sump from below the roof. The assembly is immersed in the liquid storage product and connected to an outlet at the base of the tank. Mesa's drain assemblies flex as the roof raises or lowers depending on the liquid level. Mesa's smooth internal fluidway allows water to be drained from the floating roof in the most efficient manner.

Changes in chemical composition of petroleum products have created the demand for more dynamic roof drain systems. Mesa roof drain systems meet chemical compatibility demands, perform as required by various tank designs and offer an economical solution.

Since 1967, Mesa Roof Drain systems have been field-tested and approved by refineries and storage tank facilities worldwide. Mesa drains have operated in-service for up to 30 years. Life expectancy of all drains is dependent on product in tank through out service life and are within parameters of design specifications.

 Mesa roof drains offer the following features:

• Smooth internal fluidway to ensure proper drainage--no corrugation to restrict flow or cause sediment to catch and plug up the hose.

• Operate in a vertical plane and do not scrape on the floor of the tank.

• Have consistent lay pattern ensuring that the drain stays in position as installed in the storage tank.

• Proprietary designed fittings give roof drain permanent non-leaking couplings at each end of the assembly.

• Do not add pressure to the floating roof.

• Won't cause "off-center" roof or seal gaps such as those caused by swivel joints or hard piped systems.

• Have negative buoyancy in all storage products.

• Less maintenance, less product loss, reduced shutdowns, ease of installation, maximum service life.

• Choice of single-coil or controlled, repetitive lay pattern depending on Mesa Flexible Pipe chosen for roof drain system.

Mesa Roof Drain systems do not include swivel joints, which often are prone to seizing or binding. These situations can cause leaks, stop the drain flow and even cause emission problems. A swivel joint that has become stuck can cause an off-center roof. The off-center roof creates a gap in the seal at the tank rim allowing hydrocarbon vapors to escape and pollute the air. Swivel joints also are designed to include many more potential leak points than Mesa's Resist-All-Clad, Armor-Clad or MesaFlex storage tank roof drains. Mesa's drain assemblies include permanent non-leaking fittings at each end of the assembly.

Mesa's storage tank roof drains are available in specifications to meet the demands of any storage tank liquid product. Mesa's Roof Drain Petrochemical Compatibility Chart D shows the compatibility of the standard Mesa drain assemblies in the most common products, such as gasoline, crude oil, diesel, ethanol, benzene, etc.

Mesa's roof drain systems are designed, tested and manufactured to customer specifications using  Resist-All-Clad, Armor-Clad or MesaFlex.