Page 11

DS-EN-1000 (07)

800-232-3539

610-367-2260

Fax 877-647-4011

www.penflex.com

sales@penflex.com

Temperature

Temperature Adjustment Factor Based on Braid Alloy

Saturated Steam Pressure

To Temperature (Hg)

Saturated Steam Pressure To Temperature (PSIG)

Temperature

(˚F)

304/304L

Stainless

Steel

316 L

Stainless

Steel

321

Stainless

Steel

Carbon

Steel

Monel

Bronze

1.00

150

.95

.93

.97

.99

.93

.92

200

.91

.89

.94

.97

.90

.89

250

.88

.86

.92

.96

.87

.86

300

.85

.83

.88

.93

.83

350

.81

.86

.91

.82

.81

400

.78

.83

.87

.79

.78

450

.77

.78

.81

.86

.77

.75

500

.77

.78

.81

.73

----

600

.76

.77

.74

.72

----

700

.74

.76

.66

.71

----

800

.73

.75

.68

.52

.70

----

900

.68

.74

.62

----

1,000

.60

.73

.60

----

1,100

.58

.67

.58

----

1,200

.53

.61

.53

----

1,300

.44

.55

.46

----

1,400

.35

.48

.42

----

1,500

.26

.39

.37

----

Saturated

Steam (PSIG)

Temp (˚F)

Saturated

Steam (PSIG)

Temp (˚F)

Saturated

Steam (PSIG)

Temp (˚F)

212

150

366

450

460

238

175

377

475

465

259

200

388

500

470

274

225

397

550

480

287

250

406

600

489

298

275

414

700

505

307

300

422

800

520

320

325

429

900

534

324

350

436

1000

546

331

375

442

1250

574

100

338

400

448

1500

606

125

353

425

454

2500

669

Saturated Steam

Vacuum (in. of Hg)

Temp (˚F)

----

29.84

29.74

29.67

29.39

28.89

27.99

100

26.48

120

24.04

140

20.27

160

15.20

180

6.46

200

Temperature Adjustment Factors

In general, the strength and therefore the pressure rating of

metal hose decreases as the temperature increases. Thus, as

the operating temperature of a metal hose assembly increases,

the maximum allowable working pressure of the assembly

decreases. The pressure ratings shown in the specifications

charts for corrugated and interlocked hose are valid at 70°F.

Elevated service temperatures will decrease these pressure

ratings by the factors shown in the following chart for the alloy

used in the braid wire. What also must be considered is the

maximum working temperature of the end fittings, of the hose

and their method of attachment.

For example to calculate the maximum working pressure for:
•

3⁄4” ID, 321 stainless steel corrugated hose

•

with single-braided, 304L braid

•

at 800°F.

From the corrugated metal hose specification table, the

maximum working pressure at 70°F is 792 PSIG. Multiply 792

PSIG by 0.73.

The maximum working pressure at 800°F is 578 PSIG.

Classification of Motion

Random Motion

Such motion is non-predictable and occurs from the manual

handling of a hose assembly. Care must be taken to prevent over-

bending of the hose and to avoid external abrasion of the wire

braid. An armor covering of interlocked hose provides protection

against these abuses.

Axial Motion

This type of motion occurs when there is extension or

compression of the hose along its longitudinal axis. This class

of motion is restricted to unbraided corrugated hose only and

is accommodated by traveling loops (see pg. 18) or bellows

specifically designed for this purpose.

Angular Motion

This type of motion occurs when one end of a hose assembly is

deflected in a simple bend with the ends not remaining parallel.
To find the live hose length:
L = πRØ/180 + 2(s)
L = Live Hose Length (inches)

π = 3.1416

R = Minimum Centerline Bend

Radius — Dynamic (in.)

Ø = Angular Deflection

(degrees

S = Outside Diameter of Hose

Offset Motion

Offset motion occurs when one end of the hose assembly is

deflectedin a plane perpendicular to the longitudinal axis with

the ends remaining parallel. This movement can be due to a

one-time (static) bend or movement which repeatedly occurs

slowly over time (such as thermal expansion).
•

The appropriate formula to use to calculate Live Hose

Length depends on the condition of the moving end.

•

When the offset motion occurs to both sides of the hose

centerline, use total travel in the formula;

i.e., 2 x “T.”

•

The offset distance “T” for constant flexing should never

exceed 25 percent of the centerline bend radius “R.”

•

If the difference between “L” and “Lp” is significant, exercise

care at installation to avoid stress on hose and braid at the

maximum offset distance.

L = Live Hose Length (inches)
Lp = Projected Live Hose Length (inches)
R = Minimum Centerline Bend Radius — Dynamic (in.)
T = Offset Motion to One Side of Centerline (inches)

Minimum Bend Radius Occurs at Offset Position

Moving end is free to move “out of line” at neutral position.

To find the live hose length:

Minimum Bend Radius Occurs at Crowded Position

Moving end of hose is restricted to move only up

and down as hose crosses neutral position.

To find the live hose length:

Traveling Loops

In a piping system where axial movement must be

accommodated or where the magnitude of the motion is in

excess of the limits of an offset movement, the traveling loop

configuration offers an ideal solution. In traveling loops, the

centerline of a hose assembly is bent in a circular arc. Traveling

loops accommodate movement in one of two ways. A constant

radius traveling loop accommodates motion by varying the

length of the arms of the assembly while the radius remains

constant. A variable radius

traveling loop accommodates

motion by varying the bend

radius of the hose assembly.

Both types of traveling loops

can be installed to absorb either

horizontal or vertical movement.

The constant radius traveling

loop provides for greater

movement while the variable

radius traveling loop requires

less installation space.

Traveling Loops

L = Live Hose Length (inches)
R = Minimum Centerline Bend Radius

for Constant Flexing (inches)
T = Total Travel (inches)
H = Hang Length of the Loop (inches)

Pressure Loss and Flow Velocity Information

Pressure Loss

For the same flow characteristics, the pressure loss is higher

in metal hoses than rigid piping, due to the profile of the

corrugations. As a rough estimation, expect the pressure loss in

corrugated hoses to be 150 percent higher than in new, smooth

steel pipes.

Flow Velocity Consideration

The flow velocity in corrugated metal hose should never exceed

150 ft./sec. for gas or 75 ft./sec. for liquids. When a hose is

installed in a bent condition, the flow values should be reduced

proportionally to the degree of the bend. Where the flow velocity

exceeds these rates, an interlocked metal hose liner or larger

hose I.D. is recommended.