Access
Unsafe ceilings and storage facilities can be deadly
By Patricia Thompson
Commercial property owners must not ignore the potential dangers of the failure of non-structural components of buildings - such as ceilings, parapets, facades, chimneys, partition walls and storage racks - during an earthquake, says Dr Rajesh Dhakal of the University of Canterbury.
Dr Dhakal is an associate professor in the Department of Civil and Natural Resources Engineering and a management committee member of the New Zealand Society for Earthquake Engineering (NZSEE).
He was among those responsible for inspecting buildings following the 4 September and 22 February Canterbury earthquakes.
Dr Dhakal says that non-structural and content damages were widely reported following the 4 September earthquake and contributed a major share to the overall loss.
“However, the extensive structural damage requiring demolition of a large number of buildings after the 22 February earthquake has overshadowed the significant risks posed by non-structural components,” he says.
While there was considerable focus on the loss of life in buildings that collapsed on 22 February, Dr Dhakal says that a number of fatalities were due to the failure of non-structural components, such as falling parapets and facades.
“It is important that building owners are aware of this risk. We have to change the public perception that people are safe if a building avoids structural collapse,” he says.
Dr Dhakal says that in commercial buildings, ceilings usually consist of panels resting on the flanges of a grid of lightweight inverted T-shaped beams hung from metal wires anchored to the floor above.
“Lightweight ceiling panels are now available but many buildings still have heavy panels, weighing up to 15kg. If those panels fall from more than five meters height on to people underneath, there is a reasonable chance of someone being injured or killed,” he says.
Dr Dhakal warns that we should not be fooled by the lack of ceiling-induced casualties in the two earthquakes in Christchurch; collapsed ceilings killed many people in the March earthquake in Japan.
“In many earthquake-prone countries, including the USA and Japan, seismic braces are frequently used in ceilings. However, assessments following the 4 September earthquake revealed that this wasn’t the case in Christchurch. A number of ceilings were found to have suffered dislodging or breaking of panels and failure of the grid members, perimeter angles and connections,” he says.
“Following the 22 February earthquake, the immediate need was to inspect buildings for structural damage. However, while doing so, I observed that in most buildings that were damaged structurally, the non-structural damage was even worse. In fact, I saw very few commercial/office buildings in the CBD where the ceiling was intact.
“We need to send a very strong message to building owners that they should have ceilings of their buildings inspected. Unbraced ceilings should preferably be braced and heavy ceiling panels replaced with modern lightweight panels.”
Dr Dhakal visited several commercial and industrial buildings following the two earthquakes and he found racking and shelving systems to be another area of concern. He stresses the need to change our existing installation and storage practices to achieve better seismic performance from these systems in future.
“Racks and shelves should be properly anchored to walls wherever possible, as a properly designed and adequately anchored racking system will provide the best seismic performance in relation to collapse prevention and protection of contents,” he says.
“Ideally, racks and shelves should be tied together to make the system stiffer, which considerably reduces the risk of failure and also the probability of contents falling down in an earthquake.
“However, merely providing a tie without any consideration to the likely demand will not be enough; I observed that in libraries even shelves which were tied together collapsed because ties were not strong enough to resist the tilting tendency of the shelves. However, shelves anchored to the wall or interconnected using strong ties remained intact. Strictly speaking, all members used to support/brace any non-structural component should be properly designed to resist the effect of seismic actions.”
Dr Dhakal also notes that wooden shelves in offices are often divided by timber planks which are free to slide and may fly out in an earthquake, which could easily be avoided by using stoppers at the front face.
Dr Dhakal says that damage to racks and contents is also affected by the distribution of weight. He notes that racks perform better when the weight of the contents is uniformly distributed along its length. Similarly, a rack with heavier contents in the bottom tier is significantly more stable than the same rack with heavier contents on the top.
Dr Dhakal recommends that legislation may be necessary to ensure that racks and shelves are adequately anchored and that insurers can encourage these preventive measures by offering rebates for seismically stiffened shelving and racking systems.
Further details of Dr Dhakal’s findings on the effect of non-structural damage from the September earthquake can be found in the December 2010 Bulletin of the New Zealand Society for Earthquake Engineering. Copies can be ordered through the NZSEE website: www.nzsee.org.nz
What’s your courage level?
Without exception, while Rhett Brown is speaking you can hear a pin drop. On two occasions, people were so affected they had to step away for a respite, and on many occasions I witnessed tough construction workers fighting to hold back tears. At every seminar many people came up to Rhett afterwards to thank him and express their commitment to changing their attitude on safety, for the benefit of themselves and their families.
Rhett Brown is relating his personal experiences on a two-week height safety tour of eight New Zealand regional cities, organised by Site Safe New Zealand, ACC and the Department of Labour. The tour enabled Rhett, an ex-builder and tetraplegic and now professional motivational speaker, to tell his story to over 800 people from the construction industry.
Rhett Brown worked for six years as a hammer-hand on residential building sites, then he went to work one day and never came home.
It was not a big, dramatic fall that broke his neck – just a tumble from two unsecured planks resting on deck framing, only 2.2 metres from the ground.
Rhett says, “I landed directly on top of my head. I remember seeing my feet pointing up at the sky, and the tools falling out of my apron. And I heard the crunch as my neck broke.”
As Rhett lay on the ground, summoning energy to call for help, he felt a tingling sensation go through his body and realised he was paralysed. He spent two weeks in intensive care, six months in the Otara Spinal Unit and two and a half years in a home for the elderly, but has now moved into his own specially designed house, where he has caregivers in constant attendance.
Extensive tendon surgery has given him enough movement in his right hand to feed himself, control a wheelchair, clean his own teeth, brush his own hair and shave. Everything else – including showering and toileting – must be done for him.
This recent series of seminars in regional cities followed a tour in Wellington, Auckland and Christchurch, run back in 2009. Rhett was the keynote speaker and each of the organisations provided supporting safety information with an opportunity for a Q&A session. The initiative specifically targeted work at height; however, the seminar was designed to be a wake-up call for anyone who has not given some serious consideration as to what the personal consequences will be if they fail to take reasonable precautions against being involved in an accident; and by ‘consequences’ I don’t mean the immediate injuries that may be sustained from an accident, but the long-term effect on the rest of your life.
Listening to Rhett, day after day, telling his local construction industry audiences of his accident and subsequent life, one could not help but develop a growing admiration for his courage and determination. We might think that we understand the limitations of being confined to a wheelchair, but the confinement is the least of it. It’s a total change of lifestyle. There is no more spontaneity; even minor activities have to be meticulously planned well in advance. He is constantly attended by a caregiver who handles the many things he can’t manage himself, and there is a raft of ongoing health issues.
Yes, it takes courage to live Rhett Brown’s life; I question myself as to whether I would have that level of courage. So it is with frustration that I still encounter a culture of resistance to doing a job safely.
Often individuals rationalise a failure to raise safety issues with their employers with statements such as “I’ll be picked on if I make a fuss”, or “my boss will tell me off or even send me home”, or “I don’t want to be the one who dobs our crew in” or “we won’t win any jobs if we do it the safe way”.
All of these and similar statements amount to the same thing – a lack of courage to do what is right. So consider this: if you don’t have the courage to stand up for rights to be safe at work, do you have the courage to live Rhett Brown’s life?
For most of us, being involved in a workplace accident is a hypothetical concept; there are now another 800 people who view it as a clear reality and some of them are going to do something about it, even if it is just changing their personal habits.
Jeff Strampel is a safety, health and environmental advisor for Site Safe New Zealand.
Site Safe New Zealand is the not-for-profit health and safety body for the New Zealand construction industry. For further information see:
www.sitesafe.org.nz
SARNZ wins delegated authority to issue Certificates of Competence
By Graham Burke
The major restructuring of industry training in New Zealand has created some significant concerns for the scaffolding and rigging industry.
One major threat was that changes to Opportunity The Training Organisation (OTTO) could lead to SARNZ losing control of its Certificates of Competence. However, in a very significant step forward for the industry, the Department of Labour has now given SARNZ delegated authority to issue Certificates, transferred from OTTO to SARNZ.
Other concerns do still remain – with training providers facing cut backs and numbers of Industry Training Organisations (ITOs) being very significantly reduced.
Scaffolding industry is already facing a skilled labour shortage and the expected strong upturn in construction - including the rebuilding of Christchurch, leaky home repairs and major infrastructure projects - could see forward demand increase nationally by as much as 100 per cent.
SARNZ is working with Tai Poutini Polytechnic, Opportunity Training and the Ministry of Social Development on initiatives to meet the demand for skilled and qualified people.
A Height Trade Academy is being trialed in Auckland and a pre-trade course for rigging and scaffolding in Auckland; straight to work courses in Christchurch, recruiting from the Ministry of Social Development's limited service volunteer's courses, are already running.
SARNZ continues to work with other organisations to ensure constant review and development of quality and safety standards.
Three reviews are currently in progress with Australian New Zealand standards. These are: 1576.3 proprietary and tube and coupler scaffolds, 1576.4 suspended scaffolds, and 1577 scaffold planks. These should be ready for public comment this year and, hopefully, published next year.
Vadim Spice, head of department at Tai Poutini's national scaffolding programme, has led an initiative to produce a guidance document addressing problems associated with enclosed scaffolds and temporary roofs. This has been circulated to SARNZ members and is expected to be circulated by the Department of Labour (DoL) as an alert.
The DoL has lowered the number of inspectors dramatically over the last few years to unacceptably low levels. This has put considerable pressure on our members from cowboys who do not comply with best practice and undercut those who do.
To combat this and provide the most powerful possible voice for the industry and to bring as much pressure as possible to ensure best practice in all areas of working at height in New Zealand, SARNZ aims to grow its membership base whilst maintaining high industry standards.
SARNZ was delighted to be able to celebrate some great examples of best practice at the recent SARNZ conference with the SARNZ Scaffold of the Year and the Scaffold Trainee of the Year Awards.
The Scaffold of the Year title was won by Cunningham Construction of Taranaki for its work on the Methanex Motunui methanol production facility (see the front cover of this issue of ISN).
The challenging project included erecting 260 tonnes of scaffolding to enable repair work to be carried out on the four columns at the methanol producing plant.
The towers are up to 72 metres high, impracticable for cranes, so the scaffolding was hoisted by winch and manual handling. It needed to be in place for 18 months and withstand the strong Taranaki winds.
The project required extensive safety and environmental planning. The last of the scaffolding is currently being taken down with no incidents to date.
Allan Ngatai Thompson, 25, who works for Riteway Rigging and Scaffolding in Kawerau, was presented with the Scaffold Trainee of the Year award.
Allan, who trained at Tai Poutini Polytechnic's Tauranga campus, is an excellent example of a young person who has steadily worked towards achieving the highest level of industry training.
He gained his National Certificate in Elementary Scaffolding in 2009, went on to pass his National Certificate in Intermediate Scaffolding in 2010 and completed his training with the National Certificate in Advanced Scaffolding this year.
Allan has an excellent future in the industry and there are excellent training opportunities throughout the country for young people considering a career in an industry which is very much in demand.
Tai Poutini Polytechnic, which works closely with SARNZ, runs a National Certificate in Scaffolding programme and is recognised by the industry as the preferred national trainer. It has campuses in Christchurch, Dunedin, Auckland, Wellington and Tauranga.
Graham Burke is president of Scaffolding & Rigging New Zealand.
For further information, visit: www.sarnz.org.nz