Temperature Correction Factors For Elevated Temperature Applications

As the service temperature increases, the maximum pressure a hose assembly can withstand decreases.  The material from which the hose is made and the method of fitting attachment (mechanical, soldered, welded, silver brazed) determines the maximum pressure at which an assembly can be used.

Multiply the listed correction factor times the hoses room temperature rating to determine elevated temperature maximum working pressure.

Material
Temperature °F Bronze Steel Monel Stainless Steel
Room Temperature  1.0  1.0  1.0  1.0
150  0.92  0.99  0.98  0.97
200  0.89  0.97  0.94  0.94
250  0.86  0.96  0.92  0.92
300  0.83  0.93  0.90  0.88
350  0.81  0.91  0.89  0.86
400  0.78  0.87  0.88  0.83
450  0.75  0.86  0.87  0.81
500  0.81  0.86  0.78
600  0.74  0.84  0.74
700  0.66  0.82  0.70
800  0.52  0.75  0.66
900  0.50  0.70  0.62
1000  0.65  0.60
1100  0.58
1200  0.55
1300  0.50
1400  0.44
1500  0.40

Saturated Steam Pressure Temperature

Saturated Steam Temperature ­°F
— 0
— 20
29.74 32
29.67 40
29.40 60
28.89 80
27.99 100
26.48 120
24.04 140
20.27 160
14.63 180
6.46 200
0 212
5 227
10 238
Saturated Steam Temperature ­°F
15 250
20 259
25 267
30 274
35 281
40 287
45 292
50 298
55 303
60 307
65 312
70 316
75 320
80 324
85 328
Saturated Steam Temperature ­°F
90 331
95 335
10 338
102 341
110 344
115 347
120 350
125 353
130 356
150 366
175 377
200 388
225 397
250 406
275 414
Saturated Steam Temperature ­°F
300 422
350 436
400 448
450 460
500 470
600 489
700 505
800 520
900 520
1000 546
1250 574
1500 606
2500 669
3000 696
3191 705

Flow Velocity: When to use Liners

Liquid or gas applications conveying media at high velocity should use an interlock liner in the hose assembly. This liner will decrease the turbulence caused by the high velocity and reduce the vibra­tion that will occur. A liner is recommended if the velocity is greater than the following:

Media Hose Alignment Maximum Velocity without Liner (ft./sec.)
liquid straight 70
liquid 45° bend 55
liquid 90° bend 35
gas straight 140
gas 45° bend 110
gas 90° bend 70

Conversion Formulas

Definitions Feet Per Second (ft./sec.)
gph: gallons per hour (gph ÷ ID2) x 0.0068
gpm: gallons per minute (gpm ÷ ID2) x 0.4083
cfh: cubic feet per hour (cfm / 1D2) x 3.0558
cfm: cubic feet per minute (cfm / 1D2) x 3.0558
cfs: cubic feet per second (cfs / 1D2) x 183.35

Pressure

Maximum Rated Working Pressure

The maximum pressure that a hose should be subjected to on a continuous basis. Precision Hose and Expansion Joints establishes this rating by multiplying the nominal rated burst pressure by 25%. Precision Hose and Expansion Joints Catalog pressure is calculated at 70°F.

Maximum Rated Test Pressure

The maximum pressure a hose should be subjected to during proof pressure or system testing. Hose corrugation deformation will oc­cur if the maximum rated test pressure is exceeded. The maximum rated working pressure is multiplied by 150% to determine the maximum rated test pressure.

Nominal Rated Burst Pressure

The average pressure at which the core or braid will rupture at am­bient temperature. Correct hose assembly fabrication procedure must be used to ensure the hose will meet Precision Hose and Expansion Joints Catalog pressures.

Pulsating or Shock Pressure

The performance of metal hose can be greatly reduced under this type of working pressure. Pressures are normally reduced by 50% in pulsating or shock pressure applications.

Pressure/Temperature Correction

Metal hose pressure capabilities decrease as the temperature increases. Consult the temperature correction factor table to deter­mine pressure rating at elevated temperatures.

Safety Factors

The maximum working pressure should not be greater than 25% of the nominal rated burst pressure after correcting for the application temperature. The safety factor is generally expressed as a ratio of 4:1.

Pressure Drop

A pressure drop occurs in long hose runs. The amount of pressure loss is approximately 3 times that of steel pipe.

Media

Our metal hose assembly engineer must know what the hose will convey. Matching the application piping material is sometimes used as a guide in selecting the alloy for the metal hose. Metal hose is manufactured from thin wall material and may not have the same total life a heavier wall tube or pipe of the same material. Some factors to be considered when designing metal hose assemblies include corrosion, abrasion, and viscosity of the media conveyed.

Abrasion

For internal abrasion, premature failure can occur if the media is abrasive. The use of interlock liner may extend the life of a hose assembly. For external abrasion, a protective cover may be used to extend hose life. This cover is normally stainless steel interlock hose.

Corrosion

Material selection of the core and braid should take into consideration the corrosive nature of the media conveyed by the hose assembly and the outside environment.

Viscosity

Flow of viscous media can be enhanced by incorporating the use of a jacketed hose assembly. This design utilizes an inner hose that is encapsulated by an outer hose.

Temperature:

Each hose material had unique temperature capabilities. Consult Temperature Correction Factor table for temperatures.

Testing:

Standard testing of the weld and structural components of the hose assembly include hydrostatic testing and pneumatic testing (All of our hose assemblies are 100% tested). Other testing methods used include mass spectrometer, cold shock and dye penetration.

Cleaning:

Precision Hose & Expansion Joints offers special cleaning of corrugated hose for oxygen service and other applications.