In and outs of confined spaces

Working safely in confined spaces really comes down to using the right equipment, and using it in the correct manner. Given that, Robert Weeks - a health and safety trainer - is surprised that awareness of the basic apparatus is often lacking.

I work in health and safety training, and I am always interested to discover where the gaps in trainee knowledge lie. In confined spaces, the correct approach to access and egress is crucial, but awareness of some of the basic apparatus involved is often lacking.

It is clear from my experience that people are regularly going in and out of confined spaces without using the proper combination of equipment. In recent times, workers have been known to lower others into shafts using nothing more than a rope. But, more frequently, errors arise even when proper equipment is available.

Personal injury
Many confined spaces in the water industry are accessed via a vertical shaft, perhaps the simplest example of which is a manhole. A typical manhole is equipped with a ladder - or step irons attached to the wall - providing the primary means of access and egress. This situation, with a means of climbing up and down, is one of the two general modes of confined space entry.

Naturally, entry by a manhole like this means that the Work at Height Regulations 2005 would need to be considered. This is because it is likely that a person could fall a distance - this is liable to cause personal injury. The person would therefore need to be protected against falling, using the appropriate fall-arrest equipment.

A suitable approach would probably include a full-body harness, with front-and-rear D attachment points, a fall arrest block, and an anchorage point such as a tripod. This basic system would arrest the fall, but assumes the person involved would be able to self rescue - get back to safety by using the ladder or step irons.

In order to fully comply with Regulation 5 of the Confined Spaces Regulations 1997, there must be "suitable and sufficient arrangements for the rescue of persons in the event of an emergency". The fall-arrest block should incorporate a recovery mechanism, to enable an incapacitated person to be retrieved. Such devices are now readily available, and combine both fall arrest (EN360) and a winch mechanism (EN1496 parts A & B). It should be noted that such a winch is only intended for emergency, or occasional, use.

Not all vertical access shafts are equipped with ladders or steps, in which case it becomes necessary to use access/egress equipment - also known as man-riding - to lower and raise personnel. For this application, the equipment is likely to comprise a full-body harness with front- and-rear D attachment points, a winch and an anchorage point, such as a tripod. This system now provides the primary means of access and egress.

But this system needs a secondary backup to safeguard against a catastrophic failure of the primary system - that is, the winch. The best option is, again, the use of a recovery block, as it will both arrest the fall and provide the means to recover the person.

To summarise, the two modes of access and egress are:
  • Primary - ladder, or step irons; secondary - recovery block (fall arrest and winch)
  • Primary - winch-based man-riding system; secondary - recovery block (fall arrest and winch)
Clearly in the first mode of entry - the steps or ladder - provide the primary means of access, egress and escape in the event of an emergency. But in an emergency evacuation, the risk of a fall from a ladder increases considerably due to the inherent circumstances.

While there is no rule to ensure that workers remain attached to the fall-arrest lifeline - when actually at work in the confined space - it is safer practice to stay hooked up to the line, if possible, in case of an emergency escape.

Fall arrest
In both modes of entry, a full body harness is essential equipment. Waist belts can be used for work restraint, or positioning, but under no circumstances must they be used for fall arrest. With various attachment points to a body harness, it is perhaps not surprising they are often a source of confusion.

Full-body harnesses, used for fall arrest, must meet the EN 361 standard and, as a minimum, be fitted with a rear D attachment point. This attachment point must be above the centre of gravity of the wearer, and should be adjusted so as to be between the shoulder blades, or slightly higher.

A front D attachment point may also be used for fall-arrest purposes, if fitted. Both of these attachment points may also be used for access, egress, rescue and retrieval purposes.

Some higher-specification harnesses also include a waist belt. Although the waist belt is obviously an integral part of this type of harness, the side D attachment points must once again only be used for work restraint, or work positioning - never for fall arrest.

Full-body harnesses for confined space use often feature an additional attachment point fitted from the top of the shoulder straps. The attachment point or loop complies with the requirements of EN 1497.

This attachment point can only be used for access/egress, rescue and retrieval purposes. It must not be used as a fall arrest attachment point.

Robert Weeks is business manager at CSTS.
T: 01925 244144

Tags



Topics


Click a keyword to see more stories on that topic, view related news, or find more related items.

Comments

You need to be logged in to make a comment. Don't have an account? Set one up right now in seconds!


© Faversham House Group Ltd 2008. edie news articles may be copied or forwarded for individual use only. No other reproduction or distribution is permitted without prior written consent.