Home /Pipe Fittings by Types /   Pipe Cap

Pipe Cap


Pipe caps act as protective device and are designed to protect pipe ends of various shapes. The main purpose of using pipe caps is to waterproof the connections. They are also used to close the the ends of hydraulic or pneumatic pipes and tubes. They are used in the plumbing apparatus of domestic, commercial and industrial water supply lines, machinery and processing equipment etc. They are also fitted on water pump lines with the sole purpose of removing air blocks. Pipe caps are highly demanded as an important category of pipe fittings.

Materials Used:
As a large variety of materials are used for making pipe caps, the buyer should always take care of the material of the fitting before going for pipe caps. Some of the common materials used include:
  • Aluminum
  • Nylon or polyamide
  • Polyethylene
  • Polypropylene
  • Stainless steel
  • Vinyl
  • Silicone rubber etc.

Buying Tips

Certain factors to consider are as follows:
  • Material
  • Type
  • Outer diameter
  • Thread size
  • Length and head type in shapes
How to measure pipe caps?
Take the measurements of A, B and C as shown in the figure:
Pipe Cap Common Shapes of pipe caps:
Pipe caps are available in various shapes. Having an intense knowledge about the shape of pipe cap would be beneficial for the buyer. Some of the common shapes of pipe caps are:Shapes of Pipe Caps
  • Round
  • Square
  • Rectangular
  • “U” Shape Cap
  • “I” Shape Cap
  • Hex Cap etc.
Features of pipe caps:
There are several important specifications that the buyer should consider before making bulk purchase of pipe caps. The important specifications that needs to be considered are:
  • NPT (National Pipe Thread ) size: This feature is applicable for round shaped caps, wherein the object that has to be protected has a male NPT thread.
  • BSP (British Standard Pipe) size: This size option is applicable only for round shaped caps, wherein the object to be capped has a male BSP thread.
  • Diameter: Diameter is an important dimension that is applicable only for round caps and plugs. In case of fittings having straight threads, the most important feature to be considered is the major thread diameter. However, this dimension is not an important consideration when cap, plug or object to be capped has a tapered (NPT or BSP) thread.
  • Shape: The dimension and shape of pipe caps are also very important points to consider. Pipe caps of different shapes have different features. Some features are:
    1. Round Caps: Popular features of round caps are: flange, slotted head, knurled or faceted head, retaining head, and tear tab. A flange is meant for easy removal or additional protection of pipe or tube surfaces. Flanges also help to prevent accidental pushing away of the plug through the opening. Slotted caps can be easily installed or removed with the help of a screwdriver. Knurled or faceted heads are usually designed for threaded caps and plugs only. Knurls or facets offer hassle free installation and removal. Pipe caps provided with a tear-tab or strip are easy to remove.
    2. Square or Rectangular Cap: For square or rectangular caps, length and width are the most important dimensions to consider. For rectangular caps, the width is the smaller cross sectional dimension, whereas for square caps, the length and breadth are the same dimension.

Types of pipe caps:
Pipe caps come in many different types and the type vary according to the application. However pipe caps also vary depending on their construction features and it is very important for the buyer to know the right type of pipe cap. Based on construction, pipe caps are of the following types:




Threaded Caps

Threaded Caps:

These caps are female threaded. The thread can be either straight or tapered, also referred as NPT. Generally, caps have a female thread and plugs have a male thread.


Tapered Caps

Tapered Caps:

These caps have tapered sides, which offers a close fit. Some of these fittings can be used either as a cap or a plug. Tapered caps and plugs are multi-functional and go well with male and female NPT threads, straight tubes and bars; and male straight threads. These fittings have a tapered body to provide a secure and firm friction fit while facilitating easy removal. The tapered caps are designed to provide protection for all internal and external, threaded and non-threaded fittings against damage, dirt or moisture that can occur.


Anti-roll Caps

Anti-roll Caps:

These caps are round in shape with a slightly square end. This prevents pipes and tubes from rolling.