Gasketing - Installation, Pointers & Tips

Selecting gasketing materials for particular applications is not an easy task. The variables present in a flanged connection seem endless and yet all of them must be taken into consideration to assure a proper seal. In the past, the acronym "TAMP" seemed to give sufficient information to make a gasketing recommendation (Temperature, Application, Media and Pressure). Today, items such as: the flange metallurgy, the amount of bolt thread embedment, the amount of flange rotation, the amount of bolt stretch, the additives to the media and the flange surface finish (in addition to other variables) determine how well a gasket will perform. In general, the definition of what a seal is has changed drastically over the years. Leakage measurements have gone from drips a minute to parts per million.

This web page is designed to help guide you through the various gasketing products and limit your choices. As a rule of thumb, gasket performance decreases as material thickness increases. In addition, compressive loads must be increased with thicker materials. Proper bolting sequences are necessary to ensure those compressive loads are uniform. The temperature, pressure and P x T ratings are all based on optimum conditions. When approaching those extremes, it is suggested that you consult with your Samson Industrial Sales Representative or possibly upgrade to a material that has higher ratings.

As industry standards change and new products are introduced, this page will be updated. In the meantime, we urge you to take advantage of our experienced personnel for assistance. In-plant training, technical information and gasketing recommendations all are available to help in your selection process. Please feel free to call, should you have any questions or concerns. Samson Industrial is here to help.

Temperature
In most selection processes, the temperature of the fluid at the gasketed joint should be considered first. This will reduce the number of product candidates quickly, especially as temperatures go from 200°F (95°C) to 1000°F (540°C). When system operating temperatures are approaching a particular gasket materialfs maximum continuous operating temperature limit, an upgrade to a superior material is suggested. In some situations cryogenic temperatures must also be considered.

Application
The most important information under Application is the type of flange and bolts used. The compressive load available to seal the gasket is calculated using the gasket dimensions to calculate a surface area being compressed, while the number, size and grade of the bolts are used to calculate the total available compressive load. Compressive stress available on non-standard flanges must be calculated on an individual basis. Without this information, we can not choose between various types of materials such as elastomeric (rubber) gaskets, compressed sheet and "hard" and "soft" styles.

Media
There are thousands of different fluids. We cannot, in this manual, make recommendations for all fluids. Fortunately, however, there are a relatively limited number of fluids that make up the vast majority of the media encountered in industry. System clean out and flushes should also be considered. Additional information on products versus fluids is available upon request.

Pressure
Next to be considered is the internal pressure of the fluid at the gasketed joint. We list the maximum pressure limits for each style. If severe and frequent pressure changes are involved, we should be given the details, since an alternative product
may be needed.

Pressure: psi (bar) x

Temperature: °F (°C) Values
We strongly recommend that pressure and temperature be considered simultaneously by using the following procedure:

First select the style(s) being considered for your application/service,
List the maximum pressure, temperature and P x T value for the style(s).
Make sure the actual service conditions do not exceed the style limitations in any of the three criteria.if they donft, the style(s) can be used, assuming all other requirements are met. If they do exceed any one limit, another style or styles should be considered. Rarely can a style be recommended when the service conditions of pressure and temperature are both at the maximum limits or that style.

Example:
BLUE-GARD Compressed Asbestos-Free Gasketing Style 3000

Pressure Limit: 1,000 psig (70 bar)
Maximum Temperature Limit: 700° (370°C)
Continuous Operating Temp.: 400°F (205°C)
3. P x T Limit: 350,000* (12,000)

At 1,000 psig (70 bar), maximum temperature is 350°F (180°C). At 700°F (370°C),
maximum pressure is 500 psig (35 bar).

Important:
All pressure and P x T limits in this manual are based on laboratory tests utilizing ideal gasketing conditions. Field conditions will undoubtedly affect the gasket per-formance.

We hasten to point out that this method for gasket selection is merely a general guide and should not be the sole means for selecting or rejecting a product.

*P x T based on 1/16 " sheet thickness unless otherwise stated.

Questions? Call Your Samson Industrial Representative

WARNING:
Properties/applications shown throughout this website are typical. Your specific application should not be undertaken without independent study and evaluation for suitability. For specific application recommendations consult Samson Industrial. Failure to select the proper sealing products could result in property damage and/or serious personal injury.

Performance data published on this webpage has been developed from field testing, customer field reports and/or in-house testing.

While the utmost care has been used in compiling these pages, we assume no responsibility for errors.

Specifications subject to change without notice.