EFSS has compiled below the critical articles pertaining to the issue of Harness Suspension trauma.
1. The Weems/Bishop article click here.
2. The ANSI Z359 response to the Weems/Bishop article reprinted in full:
To: Occupational Health & Safety Magazine
Regarding the March 2003 Occupational Health & Safety article ﾓWill your Safety Harness Kill You?, the American National Standards Institute (ANSI) Z359 Committee on Fall Protection and Related Systems would like to clarify the causes and risks associated with motionless harness suspension and trauma. While the committee agrees with many of the observations and recommendations made therein, there are several points that deserve clarification:
1. The article stated that suspension over 5 minutes in a safety harness can cause death, citing Paul Seddon’s report to the Health and Safety Executive (UK) entitled, Harness Suspension: Review and Evaluation of Existing Information. The UK report clearly documents the existence and importance of suspension trauma, but also shows that the related risks stem from motionless suspension (e.g. worker is unconscious or incapacitated) and not from suspension in the normal course of work. Because this important distinction is not made clear in the article, readers might mistakenly conclude that any suspension over 5 minutes can lead to death. Such a conclusion would conflict with the advice given in section 1.6.1 of the UK report that states “anyone who is suspended in a harness may be at risk of suspension trauma if they were to hang motionless in the harness and …leaving an unconscious person suspended on a rope can cause death in less than 10 minutes.”
2. The article also provided two hypothetical examples of how workers might die as a result of suspension trauma, but neither example provided a clear picture of how suspension trauma may have contributed to the workerﾒs death, nor is motionless suspension mentioned as a chief risk factor. When examples of deadly risk factors are given, a more detailed analysis should be used to reduce the opportunity for misinterpretation. This might have been done in the example of the carpenterﾒs death by mentioning that he sustained a head injury in the fall, causing loss of consciousness. Because he was working alone (i.e. had no rescue plan), and was suspended for more than 15 minutes while unconscious, he eventually died due to suspension trauma. The research shows that the level of risk to the worker suspended after a fall becomes more severe if the worker is unconscious or incapacitated by other trauma.
3. It is important to keep what is known about suspension trauma in perspective. The UK report states that over 5.8 million on-rope hours have been logged by qualified IRATA rope access technicians without any reported incidents of suspension trauma. Several deaths that occurred in caving and mountaineering are discussed in the report, but many of these had additional contributing factors such as prolonged suspension (several hours), harsh environment, and lack of harness. The death of a soldier in first aid training is discussed briefly, but he was ﾓleft unobserved for about six minutes,ﾔ suspended only by a strap around the thorax (it is not stated how long the soldier hung before he was left unobserved). The UK report does not document any worker deaths caused by suspension in a harness, but it does show an urgent need for education and action regarding suspension trauma. For more information on suspension trauma, Paul Seddonﾒs report to the HSE may be downloaded at Paul Seddon’s research for HSE.
Issues related to suspension trauma are currently under consideration by the Z359 committee. The committee is currently revising the Z359.1 standard, and may be approved by fall 2004. The revised standard will address training, use, and equipment specifications for personal fall arrest, work positioning, travel restraint, and rescue systems. For more information, please contact the Z359 secretariat, the American Society of Safety Engineers (ASSE), at 847-699-2929, attention Patrick Arkins.
Jack Dobson, CSP
Chair, Z359 ASC
3. Paul Seddon’s research for HSE “Harness suspension: review and evaluation of existing information”.
4.The April 2004 OH&S reporter printed further reaction to the Weems & Bishop article.
Dr. J. Nigel Ellis feels that while suspension trauma is a real concern workers can be and must be trained as how to alleviate the trauma while suspended and a prompt and effective rescue plan will help as well. To avoid the pooling of blood in the lower portion of the body the suspended worker must be trained to shift his/her weight from side to side frequently while suspended. A rescue plan that has the worker “down” in a few minutes (four or less is ideal) also reduces the opportunity for venous pressure to build to a dangerous level. Chest harnesses, waist belts and thorasic belts are unacceptably dangerous. A full body harness is the correct tool for suspension after a fall arrest.
Dr. Ellis, noted that harness manufacturers now supplying products to relieve suspension trauma risk by adding web foot-steps to full-body harnesses. These foot-step safety devices are to be activated by the worker in the event of a fall. The worker can then alternate between hanging and stepping side to side while awaiting rescue, thereby stimulating blood flow and alleviating the cause of suspension trauma.
5. OSHA’s article discussing the medical/physical impact of harness suspension trauma OSHA Suspenstion Trauma article.
6.Dr. Maurice Amphoux, M.A.A.C., France, highlighted dangers of prolonged suspension in fall arrest harnesses based on mountaineering and speleological experience. Motionless or unconscious suspension in strap harnesses for even a very short time, sets up a blood venus pooling effect which becomes dangerous if rescue methods do not address this effect. Oxygen or air flow into or over the respiratory tract plus slight elevation of the legs is vitally important for rescue training of fallen workers. Speedy rescue techniques are vital according to Dr. Amphoux. Conclusion: 1. Workers in pre-fall training should be told to keep body parts moving frequently in a post-fall wait for rescue. 2. The term “Prompt rescue availability” means “immediately prompt relief of suspension”. 3. Rescuers need special training for understanding suspended worker physiology.Amphoux Article: click here.
7. Suspension Trauma: A Lethal Cascade of Events by Dr. Norman Woods