The law of unintended consequences
It’s a well-established phenomenon that legislation, technical advances and major decisions are often found to produce negative, unforeseen consequences. The best examples are often found in decisions taken without studying all the facts. For example, during China’s Cultural Revolution, the Party promoted a campaign to kill sparrows to protect the rice harvest. No one had considered the job the sparrows do in eating insect pests which then ate or spoiled considerably more rice than the sparrows had ever done. An estimated 45 million people died as a result.
In the fire safety world there are some devastating examples of this law, perhaps the most notable being the effects of asbestos fibres on human lungs. Asbestos was originally perceived as an incredibly useful building material, fire resistant, a great insulator, lightweight and easy to work into different types of structural element. Sadly, around 80 years after its introduction in 1930, research showed that its fibres when inhaled caused serious lung damage. Despite this awareness, asbestos was in widespread use for a further 40 years and asbestos cement was still available in the UK until 1999. No one knows how many hundreds thousands of people were killed or had their lives impaired by the fibres but it’s no exaggeration to say that millions were (and are still) affected.
There have been less dramatic but no less problematic issues in other areas of fire protection:
- Toxicity of early fire fighting gases (such as CTC)
- Phasing out of polychorinated biphenyls as a dielectric fluid for transformers and capacitors due to neurotoxicity
- Banning of BCF and BTM because of ozone depletion
- Fires during construction of timber framed buildings and increased combustibility of structures
- Combustibility of composite panels with polyurethane cores
- Impact of new building materials – especially combustible insulation
- Poor fire stopping in ‘green buildings’
- Presence of photovoltaic panels
Other areas of concern
This list could be expanded to include an assessment of threats of fire from a number of newer products including Lithium-ion batteries, 2D electric bulbs. Consider also the Economy 7 electricity supply tariff which encourages the use of washing machines, tumble dryers and dishwashers overnight resulting in several fire deaths.
Lithium battery problems in mobile phones are known to have had a severe impact on the financial status of one manufacturer, Samsung. One estimate put the direct losses at more than US$4 billion and the decline in the company’s share price at US$11 billion.
Bringing it all together: fire in La Farge, Wisconsin
On 14 May 2013 there was a fire in a 9-year-old building occupied by La Farge’s largest employer. The fire started in a concealed roof spaces. The roof was supported by light wooden trusses and the whole space was insulated with recycled cotton/denim material.
The building was protected by sprinklers – dry in attics and wet in remainder (0.10gpm over 1950 square feet). Fire fighter access to the roof cladding was impaired by the presence of 130 photovoltaic (PV) panels and only became possible when the fire self-vented after partial collapse of the roof structure.
Metal cladding of the roof beneath the PV panels deformed as a result of the fire and the local utility found that some roof cladding was ‘live’. Current of more than 200 amps/50v DC was recorded .
When the roof trusses partially collapsed this caused a fracture in the dry sprinkler range pipes resulting in significant loss of water pressure from the mains fed sprinkler system.This loss plus firefighting demand drained all of the municipal water supply (101,000 US gallons) resulting in the need for a water shuttle using six tankers from a nearby river.
La Farge has an all-volunteer FD and was forced to call for aid from 10 other FD’s.116 fire fighters and 31 appliances responded for a fire which took 18 hours to bring under control.
Key issues of interest:
- Impact of PV panels on firefighting operations
- Early failure of lightweight roof trusses
- Combustibility of cotton insulation
- Untreated timber contribution to fire load and spread and its early failure.
- Fire demand emptied the town’s only water tank
The fire was fully investigated by the NFPA and among their conclusions were two warnings which bring together some of the threads in this article.
“The use of natural fiber insulating materials is becoming more common as a means of meeting “green building” requirements. The fire service needs to be aware when this type of insulation is used within a building, because potential fire travel in vertical and horizontal spaces will have to be accounted for”.
The report also noted that:
“Roof access amid PV panels can be difficult, with conduit and other PV system components being located throughout the roof area. PV panels cannot simply be “shut off” during firefighting operations, since they are always producing electrical current”.