Page 132 - GRINNELL Mechanical Grooved Piping Products EMEA

Grooved Couplings
Pressure and Design Data
Design
Tech Data Sheets: G810, G820, G830 Rigid Joints
GRINNELL Rigid Couplings provide rigid gripping of the pipe. They are designed to bring the pipe ends close together and to ensure the coupling clamps firmly onto the pipe OD and the bottom of the grooves. Because rigid couplings clamp around the entire
pipe surface, they provide resistance to flexural and torsional loads and therefore permit longer spacing to ASME/ANSI B 31.1 (Power Piping) and ASME/ANSI B 39.1 (Building Services) requirements.
Flexible Joints
GRINNELL Flexible Couplings act as an “expansion joint”, allowing linear and angular movement of
the pipe. They are designed with the coupling keys engaging the pipe without gripping on the bottom
of the grooves, while still providing for a restrained mechanical joint. This is particularly useful to allow for pipe expansion/contraction and piping misalignment.
Linear Movement (Flexible Couplings)
For thermal expansion with flexible couplings, the pipe ends at each joint should be fully gapped to the maximum amount. This can be accomplished
by pressurising the system and then anchoring
the system.
For thermal contraction with flexible couplings, the pipe ends at each joint should be fully butted. The system can then be anchored in place to prevent the pipe ends from opening up to the maximum end gap when pressurised.
Angular Deflection
GRINNELL Flexible Couplings are capable of accommodating angular deflection.
Expansion/Contraction
GRINNELL Flexible Couplings are capable of accommodating pipe thermal movements provided they are properly gapped and a sufficient quantity
of flexible couplings are used. Note that flexible couplings will not accommodate both full maximum linear movement and the maximum available angular deflection concurrently at the same joint.
If it is desired to have both deflection and linear movement available, then the system should have sufficient flexible joints to accommodate the requirement.
End Gap
For design purposes, the maximum pipe end gap should be reduced to account for field practises as follows:
End Gap Reduction
Maximum Pipe End Gap
Pipe Ends Gapped for Expansion
Pipe Ends Butted for Contraction
11⁄4 – 3
114.3 – 610.0
4 – 24
50%
25%
The following values should be used
as available pipe end movements for GRINNELL Figure 705, 707, and 716 Flexible Couplings:
Pipe End Movements
Pipe Size mm Inches
Cut Grooved mm Inches
Roll Grooved mm Inches
42.4 – 88.9
0 – 1.6
0 – 0.8
*
Roll grooved joints provide half the available movement of cut grooved joints.
11⁄4 – 3 4 – 24
0 – 0.063 0 – 0.188
0 – 0.031 0 – 0.094
114.3 – 610.0
0 – 2.4
0 – 2.4
The deflection published is a maximum value. For design purposes the maximum deflection should be reduced to account for field practises as shown:
11⁄4 – 3
114.3 – 610.0
4 – 24
50% 25%
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Pipe Size mm Inches
42.4 – 88.9
Deflection
Pipe Size mm Inches
Maximum Pipe Deflection Reduction
42.4 – 88.9