LPS 1194 : Issue 1.2 Requirements and testing methods for pipe hangers
- SCOPE
- DEFINITIONS
- DESIGN REQUIREMENTS
- PERFORMANCE AND TEST METHODS
- PUBLICATIONS REFERRED TO
- Table of amendments issued since publication
www.redbooklive.com
- SCOPE
This standard specifies the design and performance requirements for pipe hangers used in automatic sprinkler systems complying with the installation rules of the LPC.
- DEFINITIONS
2.1 Pipe Hanger
An assembly for suspending pipework from elements of a building structure.
2.2 Nominal size (DN)
A numerical designation of size which is common to all components in a piping system other than components designated by outside diameters or by thread size. It is a convenient round number for reference purposes and is only loosely related to manufacturing dimensions.
2.3 Proof load
The minimum load a pipe hanger must withstand without structural failure.
- DESIGN REQUIREMENTS
3.1 Nominal size
Pipe hangers shall be suitable for use with steel pipework in accordance with either ISO 65 or ISO 4200 within the nominal size range DN20 to DN250.
3.2 General construction
Hangers, other than toggle hangers (which may be attached to the swivel rod by rivets) shall be held together by bolts, or threaded rod, with nuts and washers.
Spring clips and other hangers relying on the elasticity of their materials as the means of retention shall not be used.
Open hooks shall not be used.
Split ring assemblies shall be secured by bolts and nuts.
Toggle supports shall only be used for the support of pipe sizes up to DN65.
Eye rods shall be formed from mild steel bar. The eye shall be either:
- a) Made separately from square bar and attached to the circular cross-section rod by screwing or welding; or
- b) forged integrally; or
- c) a loop or cold formed by stamping the end of the rod.
3.3 Components
Pipe hangers shall be manufactured from components complying with the following standards:
- a) BS 84: Parallel screw threads of Whitworth form.
- b) BS 1083: Precision hexagon bolts, screws and nuts (BSW & BSF threads).
- c) BS 1494: Part 1: Fixing accessories for building purposes (sundry).
- d) BS 1580: Parts 1 & 2: Unified screw threads, %” & larger.
- e) BS 1768: Unified precision hexagon bolts, screws and nuts (U.N.C. & U.N.F. threads).
- f) BS 3410: Imperial and Unified series washers.
- g) BS 3643: Part 2: ISO metric screw threads.
- h) BS 3692: ISO metric precision hexagon bolts, screws and nuts.
- i) BS 4190: ISO metric black hexagon bolts, screws and nuts. j) BS 4320: ISO metric series washers.
The same thread form shall be used for each component.
3.4 Materials
Pipe hangers shall be manufactured from materials complying with one or more of the following:
- a) BS 970: Part 1: Wrought steels for mechanical and allied engineering purposes.
- b) BS 1449: Parts 1 Steel plate, sheet and strip.
- c) BS EN 1561 – Grey castings.
- d) BS EN 10113 – Weldable fire grade structural steels.
- e) BS EN 1562 – Malleable cast iron.
3.5 Cross-sections
Pipe hanger components without protection against corrosion shall have a minimum thickness of 3mm. Components protected against corrosion to DD24 or manufactured from stainless steel to B.S.1449: Part 2 Grade 304S 15, shall have a minimum thickness of 1.2mm.
All components shall conform to the minimum material sizes shown in Table 1.
Table 1 Minimum dimensions of pipe clips, sling rods and “U” bolts
3.6 Marking
Each pipe hanger shall be marked with the following:
- a) The manufacturer’s / supplier’s name or trademark.
- b) Type designation.
- c) Nominal size.
- PERFORMANCE AND TEST METHODS
4.1 Examination Requirement
The principal dimensions and component configuration of a pipe hanger shall conform to the manufacturer’s drawings and engineering specification.
Test
Inspect pipe hanger and measure principal dimensions, compare component configuration and dimensions with manufacturer’s drawings / specification.
4.2 Resistance to deformation Requirement
The elastic and plastic elongation of a pipe hanger shall not exceed 5mm when subjected to the proof load corresponding to its size (see Table 2).
Test
The pipe hanger specimen shall be installed in accordance with the manufacturer’s instructions and a datum established on the underside of the specimen when subjected to the pre-measurement load corresponding to its size specified in Table 2. A linear instrument having a resolution of 0.01mm shall be used.
The load shall then be increased to the corresponding proof load for 2min + 30s/- 0s and whilst the load is still applied the deflection registered on the linear displacement instrument minus the datum reading (if applicable) shall be recorded.
Table 2 Pre measurement and proof loads
4.3 Strength
Requirement
A pipe hanger shall be capable of withstanding the proof load corresponding to its size without structural failure.
Test
Following completion of the deformation measurement maintain the load for a further 3 min i.e. a total of 5 mins + 30s/-0s. Record details of any structural failure.
4.4 Resistance to corrosion Requirements
A pipe hanger shall remain intact following sulphur dioxide corrosion conditioning and subsequently the elastic and plastic elongation shall not exceed 5mm and no structural failure shall occur when subjected to the proof load corresponding to its size.
Test
Dissolve 40g of sodium thiosulphate crystals in 1L of distilled water and pour solution into the glass vessel of a 10L sulphur dioxide corrosion test apparatus.
Suspend specimen for test in its normal mounting position within the glass vessel.
Set controller to regulate the temperature in the glass vessel to 45°C ± 3°C.
The temperature sensor shall be positioned centrally 45mm ± 5mm above the bottom of the vessel.
When temperature in vessel has stabilized as required, commence adding a 15.6% by volume solution of sulphuric acid (1N of H2SO4) in distilled water to the vessel at a rate of 40ml ± 1 ml/day.
Condition the specimen in the sulphur dioxide atmosphere thus generated for 16 days +3h/-0h ensuring that the vessel is emptied and cleaned after 8 days +3h/0h and recharged with a fresh solution of sodium thiosulphate and water.
After conditioning allow specimen to dry and cool to 25°C ± 10°C by storing for 7 days ± 1 day in an atmosphere with a relative humidity not greater than 70% RH.
Inspect for damage and record details.
Conduct resistance to deformation and strength tests in accordance with Clauses 4.2 and 4.3 respectively.