There are many things that will affect the ability of an individual to lift and carry particular objects and the risk that this creates, so there is no such thing as a ‘safe’ weight.
Legal requirements require avoidance or control of risk. HSE does not recommend weight limits. The Manual Handling Operations Regulations (MHOR) guidance gives basic guideline figures for lifting and lowering which indicate when a more detailed risk assessment should be carried out.
Manual handling. Manual Handling Operations Regulations 1992 (as amended). Guidance on Regulations L23 (Third edition) HSE Books 2004 ISBN 0 7176 2823 X , price £8.95.