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Handling of Dry Chlorine and the Use of Plastic Valves

Handling of Dry Chlorine & Use of Thermoplastic Valves

IMPORTANT NOTE There are many variables that affect success or failure of a particular material with any given chemical, including concentration, temperature, and the specific compound of the plastic. A material deemed suitable for a specific application does not mean that it is suitable for every application, nor that every version of that material is suitable. Plastic compounds vary between manufacturers, and the design of a valve may affect compatibility as well.
The information presented below is generally accurate, but your application may have variables that affect the performance of the material. Plast-O-Matic presents this information and any links solely as a convenience. Your distributor can help with compatibility questions, and you are welcome to contact our Technical Group at (973) 256-3000, but the ultimate determination of suitability of any information, product or material, for use contemplated by the user, the manner of that use, and whether there is any infringement of patents, is the sole responsibility of the user. To the extent that any hazards are listed, we neither suggest nor guarantee that such hazards are the only ones that exist.

In an effort to clarify and prevent possible mis-applications of Plast-O-Matic products in dry chlorine service, in either the liquid or gaseous phase, we are restating specific passages as found in the Chlorine Institute Pamphlet #6 entitled “Piping Systems for Dry Chlorine” edition #12 of August, 1989. This does not apply to chlorine dissolved in water.

Plastic Construction — Since plastics are made from hydrocarbon based materials, most plastics will react chemically with chlorine. Such reactions can be quite vigorous and dangerous in that they can result in the release of chlorine. This reactivity is avoided only with plastics in which flourine atoms have been substituted into the molecule.

Other plastics are only suitable for limited service in vacuum or very low pressure applications. Plastics have an advantage in that they are more chemically tolerant of moisture, if it is present with the chlorine. However, to some degree, all plastics are subject to permeation by liquid and gaseous chlorine and to degradation by ultra-violet light.

Plastics should be used only as specified by a designer or equipment manufacturer who is experienced in handling chlorine.

As a guide, we have listed below the four common thermoplastics used in Dry Chlorine Gas Service, with their typical limitations:

Material Abbreviation Service Maximum Temperature
Polytetrafluoroethylene PTFE Vacuum Only 280°F/138°C
Polyvinylidene Fluoride PVDF Vacuum Only 280°F/138°C
Chlorinated Polyvinylchloride CPVC Vacuum Only 150°F/101°C
Polyvinylchloride PVC Vacuum Only 130°F/ 54°C

When ordering a valve for chlorine service, please specify “Chlorine-Vacuum” with the order. “Chlorine-Vacuum” specified valves are assembled with no lubrication. Plast-O-Matic Valves are not recommended for use with pressurized dry chlorine gas.

It is important to note that any information obtained should be used only as a guide. In many cases a physical test of the material under operating conditions is the only way to ensure the success of a particular material for that application.

We recommend that anyone intending to rely on any recommendation, or use of any equipment, processing technique, or material mentioned in this website or linked websites should satisfy themselves as to suitability, and that all applicable health and safety standards are met. We strongly recommend the user seek and adhere to material manufacturers’ and chemical suppliers’ current instructions for handling.