Measuring the size of a gas pipe isn’t as simple as you may believe. The NPT (National Pipe Thread) standard is used to standardize gas pipe sizes. NPT thread sizes are smaller than standard thread sizes. Furthermore, NPT threads are tapered in order to prevent gas escape. The threads of the fittings are crushed against one other as they are tightened, resulting in a stronger seal.
A 1/2 NPT pipe thread is shown against a measuring tape in the image below. The actual measured size is slightly more than 3/4, as you can see. Because the threads are tapered, the diameter of the nipple at the end is smaller than the diameter at the base. A table with real outside thread diameter sizes for popular NPT pipe sizes may be found at the bottom of this article.
You may simply purchase fittings for your fire pit at your local home improvement or hardware store because NPT pipes and fittings are popular.
How do you gauge the size of a gas fitting?
You’ll need to know how to measure your BSP fittings if you’re unsure which type or size of fitting you have. By measuring across the thread from one side to the other, you may properly identify any BSPP or BSPT fitting. BSPP fittings are easier to measure and identify their specs with a few simple calculations.
To find the thread size, do the following:
- In inches, measure the thread’s outer diameter (OD).
- Subtract 25% from the original OD measurement.
The thread size will be 3/4 if the OD of a BSPP male thread is one inch (1″). Dash Sizes, which are a handy shorthand reference for distinguishing the type, are also shown in the chart. The thread size in this case would be -12.
The next step is to validate that the fitting is a BSP fitting by counting the number of threads per inch on it. The simplest method is to count the thread crests across a shorter length of thread, such as 1/4″, and multiply by four.
If you count 3.5 thread crests above 1/4″, for example:
- 14 threads per inch = 3.5 x 4
- Cross-reference this measurement with your thread size in the chart below.
Your measurements will be matched to the standard BSP sizes and their accompanying parameters.
How do gas line connectors get their measurements?
The first step is to determine the distance between the appliance and the gas pipe. To allow for movement and shifting of the appliance, add at least 3 inches to that distance: this is the connector length you’ll need to check for. Get something that isn’t too long or too short, as this will simply cause bending and kinking.
How do you determine the size of a propane hose fitting?
To properly measure a propane pipe, you must measure it from end to end (fitting to fitting). We sell propane hoses by the foot, which may make it easier to figure out what you need. It’s also a good idea to acquire a hose that’s slightly longer than you’ll need to account for any measurement problems.
Is the internal diameter of a pipe used to determine its size?
When it comes to pipe measuring, the inside diameter, also known as the nominal diameter, is used.
The Nominal Pipe Size (NPS) is a series of pipe diameters used in North America. The term nominal refers to pipe in general terms and assigns a non-dimensional number to the internal diameter. A 2-inch nominal steel pipe, for example, is made up of steel pipes with a diameter of 2.375 inches.
Pipes have a wall thickness that is determined by their schedule. The pipe’s outside is usually larger than its interior. The thickness of the wall causes the difference between the interior diameter (ID) and the exterior diameter (OD). The pipe’s strength is also determined by its wall thickness. The most common pipe is schedule 40, although if greater strength is necessary, schedule 80 is available.
OD and Nominal Pipe Size
The OUTSIDE DIAMETER (O.D.) of tubing is stated in inches (e.g., 1.250) or fractions of an inch (e.g., 1-1/4).
NOMINAL PIPE SIZE is the most common way to measure pipe (NPS). Despite the fact that it is related to the exterior diameter, it is vastly different. A 1-1/2 pipe, for example, has an outer diameter of 1.9 rather than 1.5. The table below compares a PIPE’s nominal outer diameter to its actual outside diameter.
The NPS corresponds to the nominal interior diameter for diameters 1/8-inch through 12-inch, but differs slightly from the actual inside diameter. Early pipe makers manufactured the lesser sizes’ walls far too thick, and in order to fix this design flaw, they removed the extra from the inside to avoid modifying the companion fittings’ sizes.
NPS refers to the actual outside diameter of sizes larger than 12 inches. The outward diameter (O.D.) of each nominal pipe size remains largely constant; alterations in wall thickness impact mainly the internal diameter (I.D.).
Wall Thickness and Pipe Schedule
Tubing wall thickness is measured in inches (.0035) or by standard gauge, which ranges from 7 (heaviest) to 22 (lightest), corresponding to a range of wall thicknesses. As the chart on the right shows, not all 12 Gauge allows for a thickness of 0.101 to 0.111. Section properties are calculated using the typical value, which is not half way between.
Pipe wall thickness is, once again, a little more challenging. To describe wall thickness, three long-standing traditional designations are used:
- Typical wall (STD)
- Extra Strong wall (XS), sometimes known as Extra Heavy wall, is a type of extra thick wall (XH)
- Double Extra Strong wall (XXS), sometimes known as Double Extra Heavy wall, is a type of reinforced concrete wall (XXH)
The American National Standards Institute (ANSI) created ANSI B36.10 in order to standardize pipe diameters. That standard expanded the range of wall thicknesses, with schedule numbers ranging from SCH10 to SCH160 (SCH160). These numbers represent 1000 times pressure-stress ratios as a rough estimate.
ANSI B36.19 extended stainless steel schedule numbers from Schedule 5S to Schedule 80S for sizes up to 12-inch. After the schedule number, the letter “S” was added to indicate that it was for stainless steel.
The traditional designations of STD, XS, and XXS, the ANSI schedule numbers, and the actual wall thicknesses all have certain correlations. In sizes up to 10-inch, STD and SCH 40 are identical; in sizes larger than 10-inch, STD has a 3/8-inch wall. XS has a 1/2-inch wall thickness. XXS does not have a schedule number, but it has a wall thickness twice that of XS in sizes up to 6-inch. Through 12-inch, stainless steel schedules 40S and 80S are interchangeable with carbon steel designations Std and XS, respectively.
The link between the various NPS sizes and Schedules and the actual Outside Diameter and Wall Thickness is depicted in the chart below.
How can you figure out what size NPT fitting you need?
Measure the diameter of the 2nd or 3rd thread on your pipe, fitting, or valve with a caliper to ascertain the NPT size, as illustrated below. Cross-reference the nominal NPT pipe size with the caliper measurement in the chart. Don’t be fooled by the NPT pipe size; the actual measurement is not the same.
How can you gauge the strength of a coupling?
Camlock couplings (also called cam couplings, camlock fittings, or cam and groove couplings) are useful equipment for swiftly connecting and disconnecting joints in a pipe line. In order for hoses and pipes to function effectively, camlock couplings must be used. However, finding the correct cam coupling size might be tricky.
It’s critical to understand how to order the right size camlock coupling for your project while employing camlock couplings. It’s critical to grasp the differences between sizes and how to measure a camlock fitting when selecting a coupling.
The diameter of the open end, or inner diameter, is used to determine the size of the female half of the coupling (also known as the coupler) (ID). The diameter of the adapter end, or outer diameter, is used to determine the size of the male part of the connection (adapter) (OD).
What are the dimensions of gas fittings?
Flaring the end of flexible “soft copper tubing with a special flaring tool and attaching flare fittings with a corresponding cone-shaped meeting surface are used to make connections. Flare fittings are commonly available in 3/8 inch, 1/2 inch, and 5/8 inch sizes.
- The outside diameter of the soft copper you’re connecting to should be the same as the flare fittings.
- Note: The photo below depicts a kinked soft copper line that should be replaced. There are two possibilities:
- Cut a new length of soft copper twisted in a spiral, flare the ends, and join with a flare fitting.
- Alternatively, as seen above, replace the damaged tubing with a flexible stainless connector.
- You may simply screw it on if the flare fitting on the flexible stainless gas line matches the flare fitting on the current gas valve.
- Replace the valve with one that has a flare fitting on one side and a 1/2-inch female pipe thread on the other side if the fittings don’t match.
- Connect the flexible gas line with the adapter that came with your hookup kit.
- Use a flare-to-pipe-thread fitting on the stove end.
- Before building threaded connections, remember to use pipe thread compound or gas-rated Teflon tape on the threads. Flare joints are self-sealing and don’t require any additional sealant.
What is the size of the fitting on a propane regulator?
Hose Emerging From Regulator A 3/8″ NPT fitting is typically found on the hose that runs from your regulator to your appliances. The female end of the supply hose is connected to the regulator, while the male end is connected to the regulator.