According to US National Fire Association, leading causes of occupancy related home fires start:
1-In the kitchen when cooking is left unattended
2-From heating systems that are not professionally checked and maintained.
3-From bad smoking habits resulting in bedding or couch/armchair smoldering.
– Fire resistance of solid log/timber homes
As a designer of log homes, I often encountered difficulties convincing local building departments all over North America of the great fire resistance of log walls. Designing solid log walls between attached garage and house living space was a problem as building inspector insisted on covering the log walls with a layer of gypsum wallboard!
In 2001 Dr. Dalibor Houdek conducted laboratory tests to measure the fire resistance of a scribe fit solid log wall.
The log wall withstood 3 hours of 1100 degree Celsius or 2000 degree Fahrenheit fire on one side before losing its load bearing capacity and integrity.
Please refer to Dalibor Houdek “ Fire resistance of log walls” published by Log Building News @ International log builders association Number 35, September 2001 for more details.
Solid log walls that are a minimum of 6” thick at the narrowest point are now accepted as the equivalent to one hour fire-resistive rated construction by building codes in North America.
As far as the walls are concerned, log walls do not have the cavities common to regular frame home construction where fire can easily spread as soon as the fire has caught one part of the wood frame.
Wood char insulates against fire:
Although logs are made of wood which is combustible, log walls act as a fire wall because the charring effect of wood (wood turning to charcoal) creates a protective barrier over the surface of massive log/timber members, acting as a strong retardant against the assault of fire.
The burning rate of massive wood varies from 1.6 inch per hour (D-fir) to 2.2 inch per hour (Pine) allowing the massive wood structure to remain sound for one, two or three hours depending on structural design.
For comparison, steel structures at 1000 degree Fahrenheit lose 50 % of its strength and quickly bend and buckle.
Please note that log/timber burns twice as fast in the vertical position compared to the horizontal (as log homes are built).
Comparing stack log/timber construction to post and beam:
Massive log/timber wall construction spreads the loads above (second floor and roof for example) into the entire log wall structure, enabling a log home to stay structurally sound for hours while on fire.
Post and beam construction will collapse much quicker because above structural loads are concentrated on a few posts that are usually exposed to fire from three or four sides at once.
Fire containment:
Log/timber homes are most likely built in rural areas instead of cities were building density is a fire issue to consider.
Log home building site locations in rural areas make them vulnerable to forest and bush fires.
Your home can be designed to minimize that risk.
-Clear all fuel sources from around your home from 30 feet to 100 feet depending on level of fire hazard in the area.
-Vinyl windows are not recommended. Metal clad windows with multiple glazing with a minimum one tempered pane are a better choice. All exterior doors should be solid core, exterior metal clad.
-Use class “A” fire resistance roof covering like concrete, clay, slate, metal tiles. Avoid asphalt or wood shingles.
-Roof fascia must be 2” nominal thickness minimum solid wood or stucco. Eaves should be enclosed with 7/8” thick stucco or 5/8” Type”X” drywall and no vents should be allowed to suck red ambers into the roof system.
-Gutters and downspout to be noncombustible material.
-Firewood storage to be at least 30 feet from house or in enclosed building.
-Concrete patio on grade around the house is a great choice. Decking surfaces, exterior stairs and balconies should be constructed of ignition resistant material or heavy timber or fire retardant treated wood.
-Install an outdoor sprinkling system to cover roof and immediate surrounding area. A man made water supply such as a pond can be a good investment with minimum 1000 gallons per minute flow for 30 minutes being recommended.
-A minimum of two ¾” water faucets with hose connection served by ¾” waterline prior to any water flow reducers at outside perimeter of the house is a must.
-Install proper spark arresters in all chimneys for fireplaces and heating appliances.
Fire detection and fire suppression systems:
Smoke alarms:
A working smoke alarm detects smoke and sound the alarm giving house occupants time to escape. They save lives at a very low cost and are mandatory in all occupancy buildings by all building codes in North America.
They should be placed at each floor, in all sleeping rooms as well just outside bedrooms. As smoke rises, best location is on ceiling or high on wall. Avoid installing them close to bathrooms, windows, ceiling fans and of course heating and cooking appliances.
As smoke alarms are battery powered or have a battery back up, test them monthly and replace the battery at least once a year. They should be interconnected and hardwired directly to house electrical wiring for new buildings.
Heat alarm in the kitchen is code in many countries as a smoke alarm is not advisable close to cooking appliances.
Residential sprinkler systems:
Smoke alarm only alert occupants to a fire in a building.
Sprinklers can contain or extinguish a fire.
8 out of 10 fire deaths happen in residential homes.
They are no instances of death by fire in residential homes equipped with a working inspected fire sprinkler system.
Municipalities across North America are adopting bylaws requiring all new homes to have sprinkler systems installed.
It is only a matter of a few more years before fire codes across the continent regulate mandatory fire sprinkler installation in all new homes.
Schools, factories, commercial and office buildings, as well as multiple occupancy housing are all required by law to have operating sprinkler systems.
There is much resistance by the home builders industry to force new homeowners to install sprinklers because installed cost adds an average of 1% to 1.5% to the overall building budget.
There is much information available online for or against home sprinkler installation. It can get quite confusing reading all the conflicting pros and cons claims.
An independent home fire sprinkler cost assessment study dated September 2008 prepared by Newport Partners Davidsonville, MD has impressed me greatly.
The research encompassed 10 very different communities in North America (9 in the USA and 1 in Canada).
The results shows that cost of sprinkler system vary significantly from $0.38 to $3.66 per sprinklered square foot depending on water supply source (municipal or on site), use of cheap CPVC piping compared to copper piping, need to use anti-freeze for freeze protection in winter…
A sprinkler system can cost from $2500 to $16 000 for an average size new home.
Most insurance companies consider home sprinkler system to be a fire protective device. However insurance discount savings only average 3.42% of annual premium or about $22 average discount savings per year.
The good news is that insurance companies do not charge any penalty or fee to cover risk of accidental water leakage from the system.
In the movies when one sprinkler goes off, all the sprinklers goes off simultaneously. That is not the case in the real world.
Only the sprinkler above a fire will go off minimizing the water damage in the house to an average cost of under $2000.00
Final word…
Sprinkler systems do save lives. It is estimated that about one life will be saved per 100 000 houses fitted with sprinklers. How much is a life worth?
Sprinklers are the fastest effective method of controlling and possibly extinguishing a home fire immediately upon detection, thus minimizing toxic smoke and fatal gases from killing the occupants.
It is hoped that the cost of home sprinkler systems will decrease as the installation of home fire protection grows.
