ISO 18752 Constant Pressure Hoses

Posted by Marek Bobik on Tue, Jan 10, 2012 @ 09:11 AM
Marek Bobik

Industry Trend Toward ISO Specs

Parker constant working pressure hoses

The industry preference is moving from using SAE specs toward using ISO specs. Hose products evolved from the SAE rated 'legacy' hoses to newer SAE rated hoses, and are now moving to ISO rated hoses.

The working pressure of the SAE rated 'legacy' hoses (R9, R10, R11 and R12) varies by size. The smaller the hose’s inside diameter, the higher the hose's working pressure. Typically, these hoses are made with the same number of reinforcement layers in all sizes. Reinforcement layers are typically wire braid or wire spiral, but can be fiber as well.

The newer SAE rated hoses (R13, R15, R17 and R19) feature constant working pressure rating  for all hose sizes. The hose may use one reinforcement layer in smaller sizes, and two or more wire reinforcement layers in larger sizes to maintain the same pressure rating for all sizes.

Today, the ISO standard is gaining popularity in hose products. It is being used by engineers with increasing frequency to identify what hoses should be used on or with i.e. hydraulic machinery, equipment or tools.

ISO 18752

ISO standard 18752 was established in 2006 for the constant pressure class hoses. It calls out performance definitions and pressure classes.

ISO 1875 Hose Grades & Types

Performance definitions classify hoses, according to their resistance to impulse, into four grades (A, B, C and D). Grades are also classified by outside diameter into standard types (AS, BS, and CS), and compact types (AC, BC, CC, and DC). Standard classes have larger outside diameters and bend radius than compact classes.

Related: Flexible metal hoses

GRADES & TYPES

GRADE

TYPE

RESISTANCE TO IMPULSE

Temperature
ºC

Impulse Pressure
as % of
Max. Working Pressure

Minimum Number of Cycles

A

AS

100

133%

200,000

AC

B

BS

100

133%

500,000

BC

C

CS

120

133%

(120% for classes 350, 420 and 560)

500,000

CC

D

DC

120

133%

1,000,000

 

ISO 18752 Hose Classes

The ISO pressure class specification addresses the most demanding and highest performance applications.

CLASS

35

70

140

210

250

280

350

420

560

Maximum
Working
Pressure

bar

35

70

140

210

250

280

350

420

560

Mpa

3.5

7

14

21

25

28

35

42

56

psi

500

1000

2000

3000

3500

4000

5000

6000

8000

 

Nominal Size

Applicable to Sizes

ISO

Inch

5

-3

N/A

6.3

-4

N/A

8

-5

N/A

10

-6

N/A

12.5

-8

N/A

16

-10

19

-12

25

-16

31.5

-20

38

-24

N/A

51

-32

N/A

63

-40

N/A

N/A

N/A

N/A

N/A

N/A

N/A

76

-48

N/A

N/A

N/A

N/A

N/A

N/A

N/A

102

-64

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

 

Posted by Marek Bobik

Topics: news, technical