Cyclic stress
The Illustrated Guide to Hot and Cold Water Services (BG 33/2014), written by Reginald Brown and published by BSRIA in 2014, in relation to cyclic stress, it states: ‘If materials are repeatedly stressed then they can develop stress cracks. These cracks form at a stress concentration point such as a sharp bend, thread root or even a surface marking. The risk of stress cracks and failure depends on the degree of stress and the number of cycles. It is permissible to use a change in direction to absorb the effects of thermal expansion and contraction (copper tube expands at a rate of 16.8 × 10-6 per °C between 20°C and 100°C) but there are guidelines on the maximum that can be absorbed. If the amount of movement is too large for an elbow then a bend or loop will decrease the stress. Guidance and calculations for the accommodation of expansion are given in CIBSE Guide B.’
--BSRIA
[edit] Related articles on Designing Buildings
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
Post-War Homes: mid-century British architecture. Book review.
CIAT reflects on the party conferences.
CIOB announce the winners of the Art of Building photography competition.
National Scheme of Delegation introduced.
The cost of employing people remains a concern.
Code of Practice for Electrical Energy Storage Systems.
ECA calls on members to comment on draft 4th edition.
Bringing together expertise and creating cultural benefits.
CIOB celebrates positive Ofsted report.
The Building Safety Regulator announces a call for evidence.
Government approach could undermine delivery and regeneration.
World's first mass timber data centre.
The overlooked environmental aspect of data centre development.
Introduction to radon awareness
New technical information sheet published by CIOB.