Fall Prevention & Protection - Truth or fiction?
August 1st 2004 Many readers will be familiar with the term mansafe and associate it with a catch-all title for all lifeline systems. The truth is that many different lifeline systems are available, from a variety of manufacturers, both in the U.K and elsewhere in the world.
Lifeline systems can vary enormously in design, aesthetics, cost and of far greater importance, safety. Effectively, you pay your money and you make your choice, unwise though that may sometimes be. In reality, choosing a lifeline system should involve a considerable amount of thought, as invariably it is a considerable cost and may literally be a once in a lifetime decision for the user
How safe is your lifeline system?
Over the last 2 years the installed safety system business ( more commonly and in some circumstances inappropriately referred to as mansafe systems) has seen a rapid growth in non-penetrating, top fixed lifeline systems. The fixing methods and lifeline support posts vary considerably. Responsible manufacturers have, and do, continue to test the fixing method and post design on a variety of roof sheets, in order to ensure that the performance of the combined system i.e. support post, fixings, lifeline and more importantly roof sheet are capable of supporting dynamic loads, consistent with lifeline systems. The assistance of roofing sheet manufacturers is not only welcome but essential to ensure design criteria. The collection and analysis of the data produced from repeated and continued testing on a variety of roofing materials is essential to ensure that an accurate assessment of acceptable loads on both structure and user are achieved. Systems designed and installed in this way are determined to be pre-engineered. The more dynamic tests carried out and the more accurate the data, the safer the installed system will be.
However not all manufacturers and installers of lifelines have access to accurate and sophisticated calculation programmes, some have little more than pre set spreadsheet information available, known to be inaccurate. As a good deal of the necessary data can not be added, such as multiple users, lanyard types, lifeline blocks, safety ropes, chucks and positioning of users at various points on the system. Unfortunately, these tests by their nature require to be conducted under test facility conditions and as such are only representative of those conditions. With support posts fixed to single section roof sheets, we are able to determine the tear out value in a number of given circumstances, and this is the best case scenario. Many providers and manufacturers of lifeline products do not have these facilities and only carry out initial systems testing to achieve the required standard insert. However, roof sheets are installed in multiples and their performance under dynamic or multiple dynamic loads, where more than one user is attached to the lifeline can not be accurately predicted.
The reality is that lifeline systems are installed on many different roof types, under varied conditions, on new and not so new buildings. The lifeline manufacturer and more importantly the installer, cannot possibly know the standard or quality of the roof fixings, but can only assume that the fixing detail and method has been carried out as the manufacturer requires. More importantly and particularly on older buildings, the lifeline manufacturer/ installer cannot know if the fixings, either of the roof sheets to the purlins or purlins to the structural supports have deteriorated, possibly due to an internal process or due to inadequate installation. If we then add to the situation, the clients requirements, particularly on new build construction, when we are often asked for the minimum provision, to satisfy legislation. With ridgeline only systems and the use of often considerable lengths of safety rope and chuck device. Frequently the safety ropes have to operate around fragile roof lights, when the system becomes unavoidably fall arrest and not restraint. Even the installation of so called swing fall posts to the edges of roofs, have limited effect and of course can be overridden. Responsible manufacturers and installers will advise on the correct, most appropriate and safest installation and responsible designers and architects will heed the advice and ensure that safe standards are implemented at the construction stage,
Lifeline systems are in danger of becoming a commodity, with minimum requirement and lowest price determining the system to be installed and not safety. Ask yourself, are you safe attaching to your lifeline system? Has the system been designed correctly for fall arrest or has it been determined to be restraint? But is it? Does your installer carry adequate insurance cover, including professional indemnity?
While top fixing is the preferred way for building owners/construction companies, as it is often more cost effective and is faster to install, it is not always the right answer when safety needs to be assured.
More articles from CSS Worksafe: |
