Non-asbestos Gasketing

In the 1970's there was no such product as Non-asbestos gasketing.  Asbestos was the product of the day and why not, it was effective, low cost and as long is it was handled properly it was safe.

In the 1980's asbestos became a dirty word, and for good reason it caused cancer.  The problem was the baby got thrown out with the bath water.  The asbestos in asbestos gasket material was embedded in the rubber it was blended with so, unless you took a grinder to the material to separate the asbestos out  and then breathed in the asbestos (which could be avoided by oiling or wetting the material first), it was not going to hurt you. Even so,  the lawyers got to work on it and effectively killed the industry. The only remaining manufacturing of asbestos gasket material is off shore.  Today, very few distributors in the USA will carry it (including this one) most will only sell non-asbestos gasket materials. American Seal & Packing has never sold any asbestos product and only sells non-asbestos compressed gasket materials.

Johns Manville took the biggest hit, once the largest distributor of gasket material in the Untied States (JM 60 was a standard), their liability was the worst since they also produced asbestos insulation. The asbestos fibers were easily released from insulation and easily breathed in.  Johns Manville eventually declared Chapter 11 and sold off divisions.  The gasket material division was later reformed as a portion of  JM Clipper and no longer sold asbestos.

In the 1980's the industry was prone.  The first company to come out with a quality non-asbestos substitute and to market it well was Garlock.  At the time Garlock was the number two seller of compressed asbestos gasket material (number 3 was Durabla Manufacturing). Garlock came out with their "Blue Guard" line and although it was not as good as asbestos in many applications it was better than a potential law suit.  Before long Garlock was number 1.  U.S. Gasket material customers were afraid of purchasing any asbestos containing product.  With the exception of the Oil refineries. 

The refineries took their case to the supreme court and won the right to maintain the use of asbestos gasket material since no other product at the time was proven to be as effective.  It did not make sense to protect workers from asbestos but not protect them from a failed gasket which in some applications (such as a steam line) can cause death.  People have been cut in half by walking past a leaking steam flange due to gasket failure.  The refineries won and still use asbestos gasket material to this day.  To the best of our knowledge that product is generally Durabla Manufacturing's "Durabla Black" a very high grade asbestos sheet.  Durabla Mfg. produces their material in Canada.

Most of todays non-asbestos gasket materials contain either Kevlar, an aramid fiber, fiberglass, carbon, graphite or another mineral fiber.  Todays manufacturers include: Garlock, Klinger (Now Thermoseal Inc.), Durabla Manufacturing, JM Clipper (Now Parker Hannifin), and DXSEAL.  Most of the manufacturers are now producing off shore.

Regardless of the manufacturer, the basics are the filler and the elastomer used.  While no two compounds (or the % of filler) are identical, the basic Elastomers are: NBR (Buna-N), SBR, EPDM or Neoprene. If you examine which material you need (as defined by the application) and select the non-asbestos gasket material with that elastomer you will usually do well.  This method will also allow you to select a competitive brand that will serve your application.  No two materials are identical so caution must always be exercised. In general the common "Binders" are:

NBR -  good for oils, gas, mild chemicals and water

SBR - good for saturated Steam, mild chemicals inert gas and water

Neoprene - good for saturated steam, refrigerants, oils, fuels, mild acids and alkalies and water.

EPDM - good for saturated steam, mild chemicals and water

Each material listed regardless of manufacture will indicate the "Binder" which makes cross referencing equal materials a much easier task.  You  should however pay attention to Tensile strength (for pressure resistance) Temperature ratings, and Compression / Recovery ratings.

You must also consider Size, Temperature, Application, Media, Pressure,  Speed (if dynamic) of your specific application.  If this is for a finished gasket you will also want to consider bolt loads, the size of bolts, the number of bolts, the bolt material and the available torque.

We at American Seal & Packing can assist you with a material selection of non-asbestos gasket materials or sell to you a non-asbestos gasket material on-line at ww.sealsales.com.  We can also offer a number of non-asbestos gasket manufacturers products to meet your specifications.