UK Product Handbook 2026 - Volume 2

Pipeline ancillaries Sight glasses

10

Dimensions/weights (approximate) in mm and kg

A

PN25 A

ASME 150 A

Size

B E F Weight

B

DN15

130

126

55 45 10

3.2

DN20

150

142

55 45 10

4.1

DN25

160

152

70 63 15

5.0

DN32

180

175

70 63 15

5.9

F (window)

B

DN40 DN50

200

199

90 80 20

9.1

230

228

90 80 20

10.9

E

Safety information, installation and maintenance For full details see the Installation and Maintenance Instructions (IM-S32-04) supplied with the product. Warning:

Under certain conditions corrosive elements in condensate can affect the inside face of the window, particularly where caustic alkali and hydrofluoric acid are present. It is recommended that the sight glass is periodically checked for thinning of the window. If there is evidence of thinning or erosion damage then the window should be replaced immediately. Always wear eye protection when viewing the contents of the sight glass. Reasonable steps should be taken to protect personnel from injury in the unlikely event that the window breaks. Installation and maintenance note: Sight glasses should have stop valves fitted on both the inlet and outlet. It is inperative that the upstream stop valve is closed first in order to prevent overpressurisation. Sight glasses can be fitted in either a horizontal or vertical line on the outlet side of a steam trap. Where the trap is a blast discharge type e.g. thermodynamic, the sight glass must be fitted at least 1 m from the trap. This is to ensure that the glass is not subjected to thermal shock or pressure. Ensure access is available for maintenance purposes Disposal The product is recyclable. No ecological hazard is anticipated with disposal of this product providing due care is taken.

7.8.16

How to order Example: 1 off Spirax Sarco DN20 SG253 sight glass having an SG iron body, removable toughened glass windows and flanged EN 1092 PN25 connections.

10.8 15

TI-P130-01 CMGT Issue 11

Page 3 of 4

SG253 Sight Glass

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