ASHRAE Pipe Elbow and Pipe Component Studies

Pressure Loss Coefficients of Threaded and Forged Weld Pipe Fittings for Ells, Reducing Ells, and Pipe Reducers

ASHRAE, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.
Technical Paper H-1405 (Available only from ASHRAE)

Pressure loss coefficients were determined for regular and long radius ells, reducing ells, concentric pipe reducers and pipe expansions. The fittings tested were two-inch threaded malleable iron and four-inch forged steel weld. A total of 250 fittings from eleven different manufacturers were tested for loss coefficients. Sample groups of production fittings of each type and from each manufacturer were tested at a constant velocity to determine the mean and variation of loss coefficients within the sample groups. One fitting of each type and manufacturer was tested for loss coefficients at a range of pipe velocities. The fittings selected from each group were the fittings that had pressure loss coefficient closest the mean loss coefficient for each group.

 

 

 

 

Pressure Loss Coefficients of Pipe Fittings for Threaded and Forged Weld Pipe Tees

ASHRAE, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.
Technical Paper H-1404 (Available only from ASHRAE)

Pressure loss coefficients were determined for pipe tees and reducing tees. The fittings tested were two-inch threaded malleable iron and four-inch forged steel weld. A total of 142 fittings from eleven different manufacturers were tested for loss coefficients. Sample groups of production fittings of each type and from each manufacturer were tested at a constant velocity and a 50% branch flow and 50% line flow to determine the mean and variation of loss coefficients within the sample groups. One fitting of each type and manufacturer was tested for loss coefficients for a range of flow distribution. The fittings selected from each group were those that had pressure loss coefficient closest to the mean loss coefficient for each group. Additional tests were later conducted to verify that the loss coefficients were independent of inlet velocity.

Pressure Loss Data for Large Pipe Ells, Reducers and Expansions

ASHRAE, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.
Technical Paper H-1672a  (Available only from ASHRAE)

Pressure loss coefficients were determined for long radius ells, concentric pipe reducers, and concentric pipe expansions. Forged steel weld fittings were tested in the sizes of 12, 16, 20, and 24-inches (30.5, 40.6, 50.8, and 61 cm) for the ells, reducers, and expansions. A total of thirty two individual fittings from four different manufacturers were tested to determine loss coefficient values. Each test fitting was examined at a specified range of pipe velocities to determine mean and variation of loss coefficients.

 Pressure Loss Data for Large Pipe Tees

ASHRAE, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.
Technical Paper H-1672b  (Available only from ASHRAE)

Pressure loss coefficients were determined for forged steel weld 12-inch and 16-inch (30.8 and 40.6 cm) pipe tees. A total of eight individual fittings from four different manufacturers were tested to determine loss coefficient values.  Each test fitting was examined at a specified range of pipe velocities to determine mean and variation of loss coefficients. The test tees were also examined for mean and variation of loss coefficients over a range of flow  distributions. Larger sizes of pipe tees were not tested because of the flow requirements and the significant cost of testing.

Pressure Loss Coefficients for Close Coupled Pipe Ells

ASHRAE, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.
Technical Paper H-1673  (Available only from ASHRAE)

Net pressure loss coefficients were studied for closely spaced or close coupled pipe ells. The test fittings were all short radius (R/D = 1) two-inch (5.08 cm) threaded malleable iron and four-inch (10.16 cm) forged steel weld pipe ells. The ells were tested in the four close coupled pipe configurations of a ‘U’ shape of two ells in-plane, a ‘Z’ shape of two ells in-plane, a ‘Torsional’ configuration of two ells out of plane, and a ‘Swing’ configuration of three ells out of plane. Each configuration was tested with different spacings between fittings of 0, 1, 2, 3, 4, 5, 10, and 20 pipe diameters. An additional spacing of 50 pipe diameters  was tested for the ‘Z’ configuration with two-inch (5.08 cm) ells. A comparison was made between the net pressure loss coefficients of the close coupled ells and an equal number of uncoupled ells. The comparison showed that the net losses of the close coupled fittings were less than those of the uncoupled fittings for configurations with less than 20 pipe diameters of spacing between fittings. For the fitting spacings greater than or equal to 20 pipe diameters, there was no effect or difference between close coupled and uncoupled pipe ells.

ASHRAE Poster Session (click to enlarge)

 Develop Design Data on PVC Plastic Pipe Fittings, Sizes 2, 4, 6, 8, and 10" Diameter (1193-RP)

ASHRAE, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

The overall objective of the present study is to develop a data base and range of accurate pressure loss coefficients (K) for production and commercially available PVC elbows, reducers, expansions, and tees. Fittings in the size range of 2 to 10 inches have been tested with both injected molded fittings and fabricated fittings. Tests also investigated the affect of misalignment and spacing in the glue connections on pressure loss. There were 240 individual components tested with a minimum of 2,440 individual tests in 20 different test setups. Testing is completed and several technical reports will be published in 2003.