Posted By Oliver Whitefield Jim You are right to ignore the 1.2m rule of thumb, as this is not an acceptable approach to the problem. Whether or not an excavation should be supported is down to a matter of risk assessment by a competent person, it depends on a wide variety of factors such as the type of soil/rock, its strength and other characteristics, the level of water saturation, the effects of wetting and drying, external loading factors, proximity of structures etc etc. Creating a battered or stepped excavation may be another option. You also need to consider the risks of items falling, or being kicked into the excavation. This leads onto the need to provide suitable protection at ground level to prevent persons on machinery falling into the hole. Finally,if this is classed as a construction site (?) the excavations should be inspected by a competent person before each and every shift and after any event likely to affect the stability of the excavation. Probably not the answers you were looking for, but the texts you have mentioned are good, though you may also wich to refer to the Con (HS&W) Regs, try INDG220 for an overview. Regards Oliver

Posted By Michael Miller All the information previously given is spot on. One small point about the 1.2m rule, remember to take into consideretion that whilst digging down, you are also piling up! This needs to be counted in the measure. A 600mm hole + 600mm of spoil etc. And having dug the hole keep excavators and dumpers well away. They have a tendancy to fall in! Mike

Posted By Ken Urquhart Jim, Try also this CIRIA publication, details below. It addresses the technicalities in a stright forward way. It also gives good guidance as to ground condition assessment etc. R097 - Trenching practice (second edition) (Non-Member price) Author(s): D J Irvine and R J H Smith Date: 1983 ISBN: 0 86017 192 2 Description: Trench collapses cause a number of deaths and injuries every year in the UK. All clients, designers and contractors concerned with trenching work are therefore urged to study this guide to safe practice and act upon its advice. The recommendations made here apply to the design and use of temporary support for trenches up to 6 m deep. The guide alerts the user to the wide range of problems in the variety of the site and soil conditions that are likely to be met in practice. The emphasis is on safe design and methods of work and particular dangers are highlighted. Both those with limited experience in trenching operations and experienced trenching practitioners will find this guide invaluable. The illustrations will be particularly helpful for training and communication with site operatives. Keywords: health and safety, ground engineering, underground construction, construction management. Price: £40.00 CIRIA is: The Construction Industry Research and Information Association and they are located at: CIRIA Web: www.ciria.org Email: enquiries@ciria.org Tel: (+44) (0)20 7222 8891, Fax: (+44) (0)20 7222 1708 Postal address: 6 Storey's Gate, London SW1P 3AU, UK Whilst you are at it why not talk to Channel 4's "Time Team", they might be interested in promoting a section in one of there future programmes to promoting the Safety aspects of Archeological work. As a programme it has great following and although the safety message they can put across would be specific to one activity, it is one that many amateurs and tempoary's get involved in and it would be a good communicator for them on Safety. Hope this is of help and interest. Regards. ken Urquhart