Black Reducing Bushes
A black reducing bush is a malleable cast iron fitting with a male-threaded large end and a female-threaded small end that reduces the size at the port of a fitting or equipment. Screwed into a tee, elbow or valve port, it allows a smaller pipe to be connected.
It is the shortest size transition at manifold, boiler and tank ports, tee branches and appliance connections. 30 size combinations from 1/2″ × 3/8″ to 4″ × 3″ are available.
Main Applications
- Reducing tee and cross branches
- Small-bore connections to boiler, tank and manifold ports
- Connecting smaller pipe to valve and pump ports
- Transitions to pressure gauge and thermometer connections
- Compressed air appliance inlets
- Size matching at gas appliance connections (in projects compliant with regulations)
Technical Data
| Fitting type | Reducing bush (male-female) |
|---|---|
| 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 | Large end ISO 7-1 R male, small end Rp female thread |
| Size range | 1/2″ × 3/8″ – 4″ × 3″ (product range) |
| Example sizes | 3/4″ × 1/2″, 1″ × 3/8″, 2 1/2″ × 2″, 4″ × 2 1/2″ (product range) |
| Number of sizes | 30 combinations (product range) |
| 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) |
| Female-female transition | With a black reducing socket |
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 | R male + Rp female | R male + 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? A reducing bush sees the same medium as the fitting it is screwed into, so it is chosen with the same surface: black on black tees and elbows, galvanized on galvanized lines.
Advantages
Shortest Size Transition
- Screws directly into the fitting port
- No intermediate socket or nipple needed
Widest Size Choice
- 30 combinations, up to 4″ × 3″
Flexible Design
- Outlets of different sizes from equal tees and crosses
Heat Resistance
- Rated 20 bar at +300 °C
Construction and Design Features
- R taper male thread on the large end, Rp female thread on the small end
- Body with hexagonal or flat wrench head (depending on model)
- One-piece cast body
- TS EN 10242 design A
Send the large (male) and small (female) size and the quantity; we will confirm the suitable reducing bush from stock right away.
How to Choose?
- Measure the port sizeDetermine the female thread size of the fitting or equipment port the bush will screw into.
- Determine the connecting sizeMeasure the male thread size of the pipe or appliance at the small end.
- Choose the right fittingUse a reducing socket if both sides are pipe and a reducing bush if one side is a female port.
- Check pressure and temperatureCompare operating pressure and temperature at the port with the design A ratings.
Complementary Products
Why ORFA?
Other Threaded Black Fittings
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Threaded black tees are equal-size fittings used to split flow in three directions on threaded black steel pipelines.
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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
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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 Plugs and Caps
Black plugs and caps are used to close the ends of threaded black steel pipes and fittings.
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Black Crosses
Black crosses are fittings that split flow in four directions on threaded black steel pipelines.
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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.
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Black Sockets
Black sockets are female threaded fittings that join two black steel pipes of the same size in a straight line.
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Black Nipples
Black nipples are short black steel pieces with male threads on both ends, used to connect two female threaded fittings.
Details →Get a quote for your project
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