Control valves

Safety valves

Page 5 of 5

Sizing and selection

Refer to:- http://www.spiraxsarco.com/resources/steam-engineering-tutorials/safety-valves/safety-valve-sizing.asp

Dimensions, weights and orifice sizes (approximate) in inches and lbs

Valve inlet

Size

Connection

Valve outlet

Size

Connection

Orifice

letter

A

ins

A1

ins

B

ins

C

ins

Weight

lbs

11⁄2"

NPT

21⁄2"

NPT

J

3.5

-

4.3

15.8

33

2"

NPT

3"

NPT

K

4.0

-

4.6

17.1

46

21⁄2"

NPT

4"

NPT

L

4.6

-

5.5

18.5

66

3"

NPT

4"

NPT

M

5.1

-

5.6

24.3

93

11⁄2"

ANSI 250

21⁄2"

NPT

J

3.5

-

4.3

15.8

38

2"

ANSI 250

21⁄2"

NPT

J

3.5

-

4.3

15.8

40

2"

ANSI 250

3"

NPT

K

4.0

-

4.6

17.1

49

21⁄2"

ANSI 250

3"

NPT

K

4.0

-

4.6

17.1

51

21⁄2"

ANSI 250

4"

NPT

L

4.6

-

5.5

19.5

71

3"

ANSI 250

4"

NPT

L

4.6

-

5.5

19.5

73

3"

ANSI 250

4"

NPT

M

5.1

-

5.4

24.3

101

3"

ANSI 250

4"

ANSI 125

L

-

5.5

5.5

19.5

82

3"

ANSI 250

4"

ANSI 125

M

-

5.5

5.4

24.3

110

4"

ANSI 250

6"

ANSI 125

N

-

7.1

6.8

26.5

187

4"

ANSI 250

6"

ANSI 125

P

-

7.1

6.8

28.5

196

6"

ANSI 250

8"

ANSI 125

Q

-

9.3

9.3

34.5

355

6"

ANSI 250

8"

ANSI 125

R

-

10.0

10.9

43.9

595

Safety information, installation and maintenance

For full details see the Installation and Maintenance Instructions

(IM-S13-33) supplied with the product.

Installation note:

The safety valve should always be fitted with the centre line of the

spring housing vertically above the valve.

SV7 safety valve selection guide

Series number

SV7

SV7

3

C

Construction

ASME section

Size and

connection

Actual

orifice area

Sq. In.

Set pressure

3 =

V =

U =

Blank =

A =

B =

C =

D =

E =

F =

G =

H =

I =

J =

L =

N =

Q =

J =

K =

L =

M =

N =

P =

Q =

R =

Cast iron

ASME Code Section I

ASME Code Section VIII

Valve without code stamp

V

B

A1

11⁄2" NPT

2" NPT

21⁄2" NPT

3" NPT

11⁄2" ANSI 250

2" ANSI 250

2" ANSI 250

21⁄2" ANSI 250

21⁄2" ANSI 250

3" ANSI 250

3" ANSI 250

4" ANSI 250

6" ANSI 250

1.374

1.968

3.054

3.846

4.633

6.830

11.811

x 21⁄2" NPT

x 3" NPT

x 4" NPT

x 4" NPT

x 21⁄2"NPT

x 21⁄2

x 3"

x 3"

x 4"

x 4

x 4

x 6"

x 8"

NPT

NPT

NPT

NPT

NPT

ANSI 125

ANSI 125

ANSI 125

A

J

C

17.123

Specify set pressure from

5 psi g to 250 psi g

180

SV7

3 A

J

-

-

-

V

180

B

A

How to order

Example: 1 off Spirax Sarco SV73-V-AJ-180 safety valve having

a set pressure of 180 psi g.

SV73 Cast Iron Safety Valve

TI-S13-25 CH Issue 11

Page 5 of 5

4.7.34