When building your storage tank system, it’s important to not only carefully consider the tank itself, but also the fittings and accessories. An important part of your tank is your manway cover. Failing to understand the purpose and function of the manway can threaten the safety of your employees and result in leaks, tank damage, and environmental hazards.

Let’s look at three things you should consider when choosing a manway cover. We’ll also introduce the best options for each consideration.

(If you're looking more information on venting, check out our online resources here: www.polyprocessing.com/venting.)

Poly Processing manufactures a wide variety of storage tank systems compatible with many different chemicals, including fuming chemicals that must be securely sealed when stored. For these chemical applications the use of a fume tight lid is usually required. Here’s a closer look at how a fume tight lid functions, when one might be required, and what options are available to meet your chemical storage needs.

We take a closer look at the useful life of a chemical storage tank and what a warranty really means to the customer.

For more than 40 years, Poly Processing Company has helped customers solve problems associated with storing hazardous chemicals.

All chemicals stored in polyethylene tanks require some form of venting in order to keep them safely stored. However, in some cases, the harmful fumes emitted from the chemicals cannot be released directly into the atmosphere. Fuming chemicals require special considerations to reduce harmful vapors before they are evacuated. There are many important things to consider when managing harmful chemical fumes and controlling air pollution.

Pneumatically-filled tanks must be properly vented to avoid offloading pressures, which increase the tank interior pressure beyond the ASTM-D 1998 regulation allowances. The right manway cover can provide the venting required to avoid this situation, but it can be difficult to know exactly which type to choose.

Typically, bulk chemical storage tanks are filled in three different ways. One option is via mechanical pump. This technique creates minimal or no additional pressure within the storage tank. A second way of filling a tank is via gravity, like in the case of leachate and condensate flowing out of a landfill basin into a storage tank.

Pneumatically filled chemical storage tanks have the potential for becoming over-pressurized. Over-pressurizing a storage tank through repeated fill cycles can damage and weaken the tank sidewalls, resulting in stress cracks and premature tank failure. Proper tank venting is needed to prevent over-pressurization.

Proper venting of chemical storage tank systems ensures safe operation and also extends the useful life of the tank. This article will examine how to determine proper venting for polyethylene chemical storage tanks.