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Dear Reader - In this issue our serialisation of 'Working With Live SRS' and 'Hydrogen On-Board Vehicles' we continue to discuss and debate the risk related issues.. As promised we intend to incorporate some of the response these articles have generated into future articles. In my last editorial I said I would be interested to know how world fire services measure their MVC/RTC rescue performance and the 'duty of care' they afford their public. Well I have heard back from many of you in respect of audit and the collection of operational stats. Judging by the response this is one topic that will definitely be addressed in future issues - let me know if you would like the news letter to move in this direction, or indeed any other direction. l - Len Watson editor - [ FEEDBACK ] -
../... Working with Live SRS
The Clam - Car on-its-roof
In Last month's ISSUE No.18 we discussed 'inverted side removal' on a 4dr car that has come to rest on its roof, where the vehicle has intact undeployed SIPS, which included head protection systems (air curtains). In this issue we continue and look at the detail that can be associated with the overturned car where roof pillars have suffered a degree of collapse.
As always we would advise all new readers that this article is one in a series and, to gain a complete understanding, it is necessary to begin by reading ISSUE 10 – 18 ‘Rescue with live undeployed SRS systems’ before continuing to read this issue – Click [ HERE ] to begin.
Before we move on to the detail involved in this area of extrication, to refresh your memory I would ask you to read the history of the incident again -
History - Single vehicle crash - The 4dr car has careered over an embankment and has landed heavily on its roof, nose down on roadway, causing partial collapse in the windscreen pillars and centre posts. The casualty is suspended up-side-down, held in place by the seatbelt.
The steering wheel airbag and the driver's pretensioner have deployed - The front passenger airbag and all SIPS (front seat mounted airbags, air curtains) and all the remaining pretensioners remain undeployed - The vehicle's battery is under the bonnet/hood and cannot be accessed - The driver is trapped in situ. For an in depth understanding of SRS deployment configurations – see [ CLICK ]
In the extrication detail in ISSUE18 we discussed the variations in inverted side removal dependant on the positioning of the SIP modules. We are now going to discuss 'The CLAM' and the likely risk critical areas that may arise and the reasons why certain risk control measures are adopted.
The Clam
- Inverted
cutting and ramming -
Working with live SIP systems - The methods of inverted cutting & ramming (with IC) outlined below highlight the critical areas of risk and the measures to control or reduce risk. Hard protection (HP) and soft casualty protection (SP) must only be used where it is considered safe to do so.
1.
Perform
glass management - Entry is
usually made via the rear door or back window
2.
Cut
all seat belts to roof pillars on the side the 'Clam' is to be performed
and remove all webbing. Where appropriate pass webbing and
tongue onto the AIO - Accident Investigating Officer. Where
the seatbelt is supporting the casualty, DO NOT cut or undo until
necessary.
PRY
BEFORE YOU CUT.
Strip sufficient trim to expose the roof's side channel, centre and
rear pillars on the working side and, where fitted, identify the IC
cylinder, pre-tensioners, connecting plugs and SIPS wiring.
3.
Remove the front door
4. Remove the rear door complete with the centre post - As the seatbelt has to be removed from the casualty prior to inverted side removal being performed, speed is vital in completing the Clam when supporting the up-side-down casualty – See last issue ‘Inverted Side Removal’
Option
1.
Option
2.
*RISK – Theoretic probability of deployment of IC and electronic SIPS seat mounted airbags and pretensioners on the working side only (Static) .../..
Useful sites:
CAUTION
- RISK CRITICAL
- When
Working With Live Systems.
On
completion of the extrication, preserve the accident scene, place warning
signs or pass 'DUTY OF CARE' on to the Police/Recovery agent
WARNING: Although the Clam offers a safe life saving evolution for those trapped in the overturned car where the roof structure has collapsed, it is essential that the evolution be practiced on the various vehicle types (4dr, 2dr, hatchback etc.) both to gain the skill level and confidence in the technique before being used at the roadside. The detail discussed in this ISSUE is suitable for the 4dr car only. The siteing of the rams alters for 2dr car and hatchbacks and there are other variations for certain types of vehicles.
Adapted
from the ‘MVA extrication PathFinder
Illustrations
from the ‘Pathfinder’ and ‘Crash Rescue – Vehicle Extrication
Rescue and In-Vehicle Trauma Care’..
Hydrogen On-Board Vehicles Hydrogen Logistics and Safety.
Hydrogen,
like gasoline or any other fuel, has safety risks and must be handled with
due caution. While people are familiar with petrol and diesel and, to some
extent LPG, handling compressed hydrogen will be new to all.
Developers must optimize new fuel distribution, storage and pump delivery systems. Consumers must become familiar with hydrogen's properties and the risks in its use as a fuel source for safe everyday use.
Getting Hydrogen to consumers.
The existing systems for the distribution of fuels from refineries to local filling stations cannot be used for transporting and storing hydrogen. New facilities and systems are needed to get hydrogen to consumers. Even with a consenting collective approach this will take significant time and money and many significant safety issues resolved and put in place.
Onboard Hydrogen storage.
The
storage of enough hydrogen onboard a FCV to allow it to travel as far as a
conventional vehicle on a full tank has proven extremely difficult and as
yet no satisfactory solution has materialised. Fuel cells are more
energy-efficient than internal combustion engines in terms of the amount
of energy used per weight of fuel and the amount of fuel used vs. the
amount wasted. However, hydrogen gas is difficult to compress in
sufficient quantity in suitably sized fuel tanks and, as such, only a
small amount can be stored onboard.
This can be overcome by increasing the pressure under which the hydrogen is stored or through the development of chemical or metal hydride storage options. Researchers are developing high-pressure tanks and hydride systems that will store hydrogen more effectively and presumably-safer.
The different meanings of safety
Neil
P. Rossmeissl, technical manager of the Hydrogen Sub-Program of the Office
of Hydrogen, Fuel Cells and Infrastructure Technologies at the U.S.
Department of Energy (DOE) states “The issue of safety has different
meanings based on the interested parties”.
As yet the unknowns facing hydrogen fuel cell development have to do with
fundamental issues such as hydrogen’s wide flammability limits. Since
the range is so great anything can ignite the fuel, the development and
safe use of these systems cannot be understated. Concerns about the issue
of permeation from high-pressure tanks cannot be dismissed especially
where vehicles are parked up for days at a time within a confined space.
The
problem of metal embitterment will likely see hydrogen onboard storage in
composite tanks made of carbon fibre with non-metallic liners. Never the
less permeation of hydrogen will still remain a problem.
Because
hydrogen is colourless, odourless, and tasteless, leak detection poses a
problem. Odorants aren’t appropriate for hydrogen because they
contaminate the catalysts that are a key to fuel-cell operation, so the
traditional human-sense-of-smell approach had to be taken out of the
equation. Therefore all system designs must incorporate sensors and
controls to determine if any leak is present. Due to the buoyancy of
hydrogen, all of the instruments must be mounted in elevated positions,
thus limiting flexibility of design.
Motor Companies have developed many safety systems. Ford’s hydrogen-detection system consists of four sensors, two in the luggage compartment, one in the engine and another in the passenger compartment.
Eight small
fans continuously vent the vehicle during operation and refuelling.
Although Hydrogen is non-toxic, where it displaces the oxygen in the air
in a confined enclosed area it can lead to asphyxiation.
Motor
Companies have conducted numerous crash tests to see what would happen if
the hydrogen tank on its vehicles was punctured or damaged. Surprisingly
their engineers report that the liquid hydrogen dissipated harmlessly
Present
H&S rulings provide requirements for fire protection at facilities
storing liquid and gaseous forms of hydrogen. In general they require that
“personnel shall be instructed that hydrogen flames are practically
invisible,” and trained in the knowledge that with Hydrogen fires the
supply must be shut off because of the danger of re-ignition or explosion
if the Hydrogen flame is extinguished prematurely.
Combination fog and solid stream nozzles are preferred for surrounding fire control. Small hydrogen fires can be extinguished with portable dry-chemical extinguishers or with carbon dioxide or nitrogen. And we must never forget that re-ignition will occur if a metal surface or material hot-spot isn’t cooled sufficiently.
Safety Issues and Concerns
I
recently read an article which stating that - The
hazards of handling this gas must be kept in perspective, despite
incidents such as the Hindenburg disaster. Unknown to many, this incident
was not directly attributable to hydrogen, but to extreme flammability of
the outer varnish containing aluminium particles when the vessel was
struck by lightning …… Contrary to what some people may believe, it is
not inherently explosive. It must be mixed with air or oxygen before
detonation can occur. Since it has such a high dispersion coefficient, it
dissipates rapidly. Because of this, it is almost impossible for a
hydrogen explosion in an open area, and a hydrogen fire will burn out much
faster than a petrol fire.
While
there are some truths in this statement it sadly denies any understanding
of the likely real-world hazards and likely risk propagation that will
manifest with hydrogen on board vehicles. I suppose in a way ‘denial’
of risk is my greatest concern.
If
the safety issues and risks outlined in this series of articles are not
addressed and solutions found and acted on, the mass production of the FCV,
hydrogen filling station pump-delivery-systems, underground and multi
storey car parks, domestic garaging and other degrees of associated risks;
the wide scale introduction of FCV’s is destined to have a bumpy ride.
At every quarter we are assured that safety-standards are set to keep pace with technological breakthrough. I along with many of my associates and colleagues have our reservations and, as always standby to pick up the pieces.
NEWS & VIEWS -
Exhausted firefighters struggle with colleague's death - 7/04/2008
Firefighting colleagues of Derek Lovell are finding it hard to come to terms with his death.
Mr Lovell died from the injuries he sustained in an explosion, which occurred as he and seven colleagues responded to a blaze at Icepak Coolstores in Tamahere, south of Hamilton, on the Saturday afternoon.
Six of the firefighters remain in hospital, two of whom are critical - read full story [CLICK]
LA Firefighter killed in massive explosion -
One
Los Angeles firefighter was killed and another injured Wednesday afternoon
in an explosion that rocked a Westchester business district as rescuers
were investigating reports of earlier blasts and smoke pouring from
buildings.
The dead firefighter, who was identified as Brent A. Lovrein, 35, was
blown back and possibly hit by building material when an electrical vault
blew apart, ripping a gaping hole in an office building at Sepulveda and
La Tijera boulevards - read full story [CLICK]
Airbag Deployment in Low Speed Crashes Increases Injury
Boston, MA--Approximately 50 million vehicles in America, from model years 1986-1997, are equipped with first-generation driver-side airbags. A study by Maria Segui-Gomez, MD, Sc.D., done when she was with the Harvard Center for Risk Analysis, finds that the deployment of these airbags in low speed crashes actually increases the likelihood that a driver will be injured. These injuries range from minor to serious and even fatal. Women are more likely to suffer airbag-induced injuries than men.
The study, published in the The American Journal of Public Health, is the first in the peer-reviewed scientific literature to document that first-generation driver-side airbags, while saving lives and preventing serious injury in higher speed crashes, actually increase injuries in lower speed crashes. Segui-Gomez, who is now a faculty member at the Johns Hopkins School of Hygiene and Public Health, points out that these results may not apply to second-generation airbags, installed beginning in 1998, which were not covered in the study.
The study finds that deployment of airbags at crash speeds below 20 miles per hour increases the likelihood of injury among all drivers. Broken down by gender, the crash speeds are 32 MPH for women and 8 MPH for men. In crashes above those speeds, the airbags have a net protective effect. Below those speeds, they have a net injurious impact.
According to John Graham, Director of the Harvard Center for Risk Analysis, "These findings about airbags deploying in low speed crashes suggest that airbag suppliers and vehicle manufacturers need to reconsider the setting of airbag deployment thresholds."
COMING NEXT ISSUE
Firefighter Protocols for Life Threatening Situations - Continual risk assessment and emergency standard operational procedures and their pitfalls.
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