Black Plugs and Caps
A black plug is a malleable cast iron fitting that closes the open end of a threaded black steel line or a fitting permanently or temporarily. The male plug screws into a female port, while the female cap screws onto a pipe end.
Spare ends of manifolds and crosses, line ends to be extended later, and test and drain ports are the main applications. Plugs come in 10 sizes from 3/8″ to 4″, and female caps in selected sizes.
Main Applications
- Closing spare ends of manifolds, tees and crosses
- Line ends to be extended later
- Closing the line end during pressure testing
- Closing drain and air vent ports
- Unused ports on boilers and tanks
- Dead ends in gas lines (in projects compliant with regulations)
Technical Data
| Fitting types | Male plug; female cap |
|---|---|
| Product standard | TS EN 10242, design symbol A (manufacturer information) |
| Material | Blackheart malleable cast iron B 350-10 (sales sheet information) |
| Surface | Black, without galvanized coating |
| Thread (plug) | ISO 7-1 R taper male thread |
| Thread (cap) | ISO 7-1 Rp female thread |
| Plug sizes | 3/8″, 1/2″, 3/4″, 1″, 1 1/4″, 1 1/2″, 2″, 2 1/2″, 3″, 4″ (product range) |
| Cap sizes | 1/2″, 3″ (product range; others depending on model) |
| Permissible pressure | 25 bar, −20 … +120 °C (EN 10242, design A) |
| Pressure at high temperature | 20 bar, up to +300 °C (EN 10242, design A) |
| Leak test | At least 5 bar air or 20 bar water (sales sheet information) |
| Installation | Thread sealing tape, hemp or anaerobic sealant |
Material Options
| Part | Black malleable iron | Galvanized malleable iron | Stainless steel |
|---|---|---|---|
| Body | Blackheart malleable cast iron B 350-10 | Malleable iron EN-GJMB-350-10, hot-dip galvanized | Investment casting or bar, depending on model |
| Surface | Black, uncoated | Zinc coated | Stainless, uncoated |
| Thread | Plug R male, cap Rp female | Plug R male, cap Rp female | Depending on model |
| Pressure rating | 25 bar −20…120 °C, 20 bar 300 °C (EN 10242) | 25 bar −20…120 °C (EN 10242) | Depending on model |
| Suitable media | Closed heating water, gas, compressed air | Drinking and domestic water, fire water | Corrosive media and media requiring hygiene |
Which material? The closed end sees the same medium as the rest of the line, so the plug is chosen in the same material as the pipe and fittings: black plugs on black lines, galvanized plugs on galvanized lines.
Advantages
Quick Closing
- Fitted with a wrench and removed when needed to reuse the end
Installation Ready for Expansion
- A spare end can be opened for a branch later
Easy Testing
- Line ends are closed with plugs during pressure tests
Two Types
- Plug for a female port, cap for a male pipe end
Construction and Design Features
- Plug with R taper male thread and wrench head
- Cap with Rp female thread and closed bottom
- One-piece cast body
- TS EN 10242 design A
Send whether the port to be closed is female or male threaded, its size and quantity; we will confirm the suitable plug or cap from stock.
How to Choose?
- Determine the end typeChoose a male plug to close a female port and a female cap to close a male pipe end.
- Measure the sizeDetermine the port or pipe size in inches.
- Consider removalIf the end will be opened later, choose an easily removable sealing material.
- Check pressure and temperatureCompare the highest pressure at the closed end, including test pressure, with the 25 bar limit.
Complementary Products
Why ORFA?
Other Threaded Black Fittings
Threaded Black Tees
Threaded black tees are equal-size fittings used to split flow in three directions on threaded black steel pipelines.
Details →
Black 45° Elbows
Black 45° elbows are fittings used to change direction by 45 degrees on threaded black steel pipelines.
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Black Pipe Crossover Bends
Black pipe crossover bends are curved fittings used to pass over another pipe on threaded black steel lines.
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Black Unions
Black unions are fittings that join two threaded black steel pipes in a way that can be taken apart again.
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Black Elbows
Black elbows are fittings used to change direction by 90 degrees on threaded black steel pipelines.
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Black Reducing Tees
Black reducing tees are fittings used to take a smaller branch off the main run on threaded black steel lines.
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Black Conical Unions
Black conical unions provide a tight, removable connection on threaded black steel pipes through a conical seat.
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Black Crosses
Black crosses are fittings that split flow in four directions on threaded black steel pipelines.
Details →
Black Street Elbows
Black street elbows have one female and one male threaded end and change direction on black steel lines without an extra nipple.
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Black Reducing Sockets
Black reducing sockets are female threaded fittings that join two black steel pipes of different sizes.
Details →
Black Sockets
Black sockets are female threaded fittings that join two black steel pipes of the same size in a straight line.
Details →
Black Nipples
Black nipples are short black steel pieces with male threads on both ends, used to connect two female threaded fittings.
Details →
Black Reducing Bushes
Black reducing bushes are fittings with male and female threads used to change pipe size on threaded black steel lines.
Details →Get a quote for your project
Our sales team will prepare the best solution for your needs.