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Read what others have already asked. Below is a list of frequently asked questions, divided by the following topics:

Gasket Selection & Sizing

Simply put, it’s basic math. Our engineers make sure that there is enough “stretch” on the gasket to keep it in place on the spigot during the homing process, and enough rubber volume to adequately fill the space provided by the joint design, all without putting too much rubber in the joint which could lead to an inability to home the pipe or manhole sections properly or to bell breakage.

Yes, a single off-set joint in combination with a profile gasket can be used as a substitute for o-ring gaskets and confined o-ring joints. However, the gaskets must be manufactured from a material that can meet the material requirements for ASTM C361. Also, job site conditions must be evaluated by HK engineers to ensure a proper level of safety in the performance of a profile gasket and single off-set joint. Additionally, approval will be based on the configuration of the alternate joint design. Final approval must be obtained from the project engineer or owner prior to the start of the project. If we determine our gaskets, in combination with our customer's manufactured joint, will meet the requirements of C361, Hamilton Kent will supply the necessary documentation of the calculations and information to the specifying engineer for consideration of approval of the alternate joint design.

Gasket Installation

While we never recommend leaving gasket exposed to the elements for any period of time, in this situation they can be left for 6 months to 12 months. In order to protect from degradation due to UV exposure, we recommend covering the gasket with an opaque UV wrap until the box culvert sections are shipped to the job site.

While it’s rare, during the splicing process or while injecting the silicone lubricant into the rolling tube, sometimes extra air becomes trapped in the tube of the Superseal gasket. During the homing process, the rolling tube gets squeezed and can rupture if too much air is in the tube. This part of the gasket is not responsible for any of the sealing properties of the gasket (the “body” of the gasket is responsible for creating the seal). As such, this will have no effect on the performance of the gasket.

As rubber gets cold, its durometer increases (in other words, it becomes harder). While standard compound gaskets will remain in spec even in the coldest temperatures, the harder a gasket becomes, the more the insertion force will increase. So, if you can keep the gaskets in a warm environment just prior to installation this will make the homing process easier to perform.

Gasket & Pipe Testing

While it’s easy to suspect the gasket when a joint leaks, it is only one variable among many that can lead to joint leakage. Other things needing to be investigated: are there bugholes in the bell where it meets the spigot? Is the step (single offset design) properly formed all the way around? Has worn or damaged tooling caused the finished product to become oval and out of spec? These are some of the factors that individually or working in concert that can lead to joint leakage. Please contact your HK representative to discuss. Our team of engineers are available to help you with these issues.

The Hamilton Kent engineering department provides these drawings upon request for our customers.


The oil-resistant gaskets generally may feel like they are a little bit harder than an ordinary rubber gasket. They may also be a little more difficult to put on the joint, and may require a little higher force to home the pipe in the field. For more information on the difference between rubber compounds, please visit the Resources - Tech Notes section of this website.

The base compounds used to make Nitrile are very expensive and have a very short shelf life. As such, HK generally orders the base compound only when it’s needed to avoid costly spoilage. In addition to the shipping time, more time is also required for the compound to acclimate to the environment before it can be processed into a finished product. Also, splicing of Nitrile gaskets is tricky and our production team needs more time to devote to this part of the process. Finally, our QC personnel need time to thoroughly check the gaskets or connectors to ensure that the product we deliver will meet all required specs.

Provided the correct material is utilized for the conditions, gaskets will continue to perform properly for the life of the structure or pipe in which they were installed.

These materials are primarily going to be utilized in rubber gaskets or connectors when they are likely to be exposed to petroleum-based substances, such as oil, jet or vehicle fuel, jet de-icing chemicals, etc. Exposure to hese substances likely would cause gaskets and connectors made of ordinary rubber compounds to deteriorate more rapidly than they are designed. Nitrile and Neoprene gaskets and connectors will maintain their physical properties and provide the intended seal even when in contact with petroleum-based materials. Please note that gaskets and connectors made from these compounds can take as much as 4-5 weeks to deliver and cost 4-5 times as much as ordinary rubber components. For more information on oil-resistant gasket materials, please visit the Resources - Tech Notes section of this website.

Specifications & Certifications

Many are not aware that the rubber gasket part of ASTM C 443 was removed and a separate standard was created for rubber gaskets, ASTM C 1619. C 1619 is now a reference standard in C 361, C 443, C 1628, and C 1677. Most of the gaskets supplied by Hamilton Kent meet or exceed the requirements of C 1619, Class C, and C 1619, Class D for oil resistant gaskets.

Gaskets usually have printed on them all of the specifications which they meet. Additionally, Hamilton Kent can provide documentation showing the quality assurance testing completed on these gaskets according to the specifications for your project. HK does not and will not cut corners; you can be assured the gaskets you receive are the correct ones for the project.


Assuming they are kept in a dry location, free of ozone and away from UV light, regular rubber gaskets can be stored up to 3 years after their manufacturing date and safely remain within specifications. Beyond 3 years after manufacturing, HK recommends that the Durometer (hardness) of the rubber be tested to ensure it is still within specifications before utilizing. You can contact the HK technical department for recommendations on Durometer (Shore A) gauges.

If they are stored in a dry location, free of ozone and away from UV light, Nitrile gaskets should remain within specifications for at least one year after the their manufacture date. Beyond one year, the Durometer (hardness) of the rubber should be checked prior to each shipment of these gaskets to ensure they are still within specifications. You can contact the HK technical department for recommendations on Durometer (Shore A) gauges.


Base compounds used to make rubber gaskets such as polymers and monomers are the same chemicals used to make any rubber product. Manufacturers of car tires are the biggest consumers of these base compounds. Presently, BRIC countries (Brazil, Russia, India and China) are purchasing unprecedented amounts of vehicles which in turn creates shortages and drives up the prices. We work very closely with our suppliers to try to mitigate these effects for our clients.

There are several reasons why the Tylox SuperSeal gaskets are more expensive than a traditional profile gaskets. First, due to the delicate nature of the rolling tube and the challenge to manufacture it perfectly, there tends to be a higher scrap rate for this gasket type. Second, the rolling tube requires additional rubber material in the production process. Third, each SuperSeal gasket requires injection of a silicone lubricant into the tube and subsequent mechanical rolling of the gasket to spread the lubricant within the tube, which adds to the labor and machinery time and cost.

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How do you test a gasket or prevent infiltration through manhole covers? What standards and certifications govern Hamilton Kent products? Get answers to common infrastructure questions in our FAQ section.

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