Measuring Boiler & Tank Gaskets
Identifying which gasket you need for your boiler or tank can be tough. Access ports and covers can come in a variety of shapes, sizes and materials. This is a quick and easy guide to help you identify, measure and order the correct gasket for your tank or boiler. If you need any help selecting which gasket is right for you, just CONTACT US and we can help guide you to make sure you get the right thing!
IDENTIFYING THE SHAPE OF YOUR GASKET:
Most manholes, handholes, access ports and covers on tanks are one of the three shapes shown below, but unfortunately there can also be a wide range of other shapes and sizes. If you don't see your gasket below, please CONTACT US and one of our engineers can help determine what shape gasket you need.
MEASURING YOUR GASKET:
Once you have determined the shape of your gasket, you will need a few basic measurements to be able to order the correct size of gasket. Below is a quick guide for measuring some common types of tank gaskets.
Boiler & Pressure-Vessel Access Ports
Commonly known as a "manhole" or "handhole", most access ports on boilers and pressurized tanks are installed inside of the tank and held in place by clips (or crabs). As pressure builds inside of the tank, the cover plate is pushed out against the gasket. With the correct gasket in place, this creates a strong and lasting seal for the port.
Most of these internal-style manhole or handhole ports will have an oval or obround shape. To determine your gasket's size, you will need to record the INSIDE LENGTH, the INSIDE WIDTH, and the FLANGE WIDTH. For the width and length be sure you are measuring the inside of the gasket and not the outside. The required measurements can be obtained by measuring the gasket, the cover-plate, or both!
Once you have the measurements of an oval/obround gasket, you can find your size and purchase gaskets here:
GADDIS COMPANY - MANHOLE & HANDHOLE GASKETS
Round Doors & Covers
On low-pressure tanks, many doors and covers will be a circular shape. There are two common types of round gaskets. Many bolted covers will utilize a "full-face" gasket that sits across the entire sealing surface and includes holes for each bolt to pass through. Other applications use a ring style gasket that is a solid gasket with no holes. Ring gaskets either sit in a groove or they sit on a flat flange, just inside of the bolts.
To determine the size of a round gasket, you must record the measurements shown in the following diagram.
Once you have obtained the measurements above, it is best to check if your gasket matches a standard ANSI flange size. A chart of these standard ANSI flange sizes can be found here on Garlock's website:
RING & FULL-FACE GASKET DIMENSIONS
If you have a standard ANSI flange gasket, you can find many in-stock gaskets in various materials on the Gaddis website at the following link:
GADDIS COMPANY - FLANGE GASKETS
If your gasket is not matching up to a common size, please CONTACT US and one of our engineers can help verify the size and provide a quote for the correct part!