After getting an fire evacuation call at 1 am early Monday morning 9 October 2017. It turned out that I did not need to evacuate, but the Mendocino lake complex fire was lighting up the sky. Here are photos of fire attack helicopters and aircraft flying over my house fighting the fire. Since then I've been studying what I can do to reduce the chance that my house will burn. The three elements of fire (Wiki) are: fuel + air + heat.
When I started this page I thought it would only apply someone living in a jungle or forest. I also thought fire spread like a water wave where the fire front moves and ignites all the flammable material in it's path. Now I know both of these ideas were wrong.
How Fire Spreads
Fire can spread like a wave with direct flame contact if it has fuel. Fire can spread by radiant heat, but that requires both a large fire and long exposure. Most trees burn too quickly to ignite houses at one hundred feet away, but can ignite nearby trees. Fire also spreads by means of firebrands or hot embers (Wiki). But these embers are small and can only ignite tinder (Wiki: Tinder) such as dry leaves, pine needles, fir bark, &Etc. which in turn lights kindling (Wiki) such as small plants with dead branches or plants/bushes that are dry, or dry wood like wood shingles or wood fencing. Kindling can in turn light larger pieces of wood, like wood siding on a house, 4x4 posts &Etc..
The key factors in the spreading of fire are: Weather (mainly humidity and wind), topology (fire tends to move up hill if there's no wind) and Fuel (fire can not spread if there's nothing to burn).
The above ideas are codified in the Notice of Defensible Space Inspection. In the upper left corner on the back side: "Hardening Your Home - Flying embers can destroy homes up to a mile ahead of a wildfire. Prepare (harden) your home now before a fire starts."
Cal Fire Property Inspection Guide - 65 pages
How fire spreads has nothing to do with the location of a house. That is to say houses in a city or suburb need defensible space just as do houses in the jungle or forest. But there's a problem in that the spaces involved are:
The problem for city lots is they are too small to meet the zone sizes, hence these rules are not applicable. But, fire does not recognize this limitation.
- Remove all branches within 10 feet of a chinneyh or stove-pipe.
- Zone 1 (within 30 feet of the house) remove all tinder and kindling, no wood piles
- Zone 2 (between 30 and 100 feet of the house) rules about removing plants, shrubs and trees
The first thing is to remove a lot of the undergrowth that is potential fuel. The street was not visible in either of these views a couple of months ago. More needs to be removed in these views and in adjacent areas. When I first moved here you could not even walk in these spaces. Notice that the vegetation is so dense across the street that you can not walk there.
Fig 1 Click photo to see larger version, then look just to the left of the foreground tree (at the street) to see fire hydrant.
Fire Fighting Equipment
As part of the second step I'm investigating getting some wildfire fighting equipment. A number of people in the recent fire saved their houses or the houses of a neighbor/friend/relative by fighting it themselves. Note that there's no way the local fire departments could respond to all the calls for help.
My son who lives in Santa Barbara says there's almost a fire engine in everyone's driveway to protect houses from the Thomas Fire (Wiki).
Areas that were evacuated and they had police road blocks, with the rule once you leave the area you can not return. But they would not force anyone to leave. So those who stayed had a neighbor/friend/relative who could meet them bringing needed supplies.
Fire Apparatus (Wiki) "any vehicle that has been customized for use during firefighting operations."
It happens that there's a fire hydrant in front of my property. It's made by Clow and is a wet barrel type.
Wet vs. Dry Barrel Fire HydrantsIn areas where it freezes in winter the dry barrel type hydrant is used. These have the valve located below the freeze depth and in addition have "slop" in the connection between the valve and the actuating mechanism. This allows for a bleed valve to be opened to drain the hydrant into the nearby ground so that no water is inside after it's turned fully off. The valve should be either fully opened or fully closed. If in an intermediate position water will be forced out of the drain and might erode the ground nearby.
In warmer climates, like here in California, the valves are directly in line with the outlet fittings and so can be used for flow control as well as on/off.
Note that the outlets are 2-1/2" and 4-1/2". The nuts are pentagon shaped, not the hexagon shape that's commonly used on nuts and bolts, so standard tools will not work. Also vice grips, pliers &Etc. will fail and damage the pentagon shape.
I'm trying to learn why this and other hydrants on my street are painted white.
As of 2 Jan 2018 I have not had a return call from the local fire department (I think they are in S. California on mutual aid - Wiki).
The wiki page on fire hoses misses some the functional differences in fire hoses (Wiki).Wall Stiffness
I would say the most important hose parameter is wall flexibility.
Flexible wall tubing will collapse when a vacuum is applied. The lower radiator hose in a car (feeds the water pump) has a metal helix inside to prevent collapse which would have the effect of blocking water flow.
Note that the tubing connected to a vacuum pump has flattened.
Note that the stiff wall tubing does not colapse.
Common garden hoses (Wiki) have stiff walls and are easy to use. For example if a common garden hose is lying on the ground and the faucet is turned full on, the hose will not move. You can hold a garden hose nozzle in one hand and point it left or right without resistance from the hose.
Cloth fire hoses (Wiki) have very weak walls which makes them much lighter in weight and store in a much smaller volumeFlexible wall hoses will not flow water when folded, for example when in a pin rack (Wiki photo) inside a building or when on a reel. These hoses need to be pulled out so there are no kinks before the water is turned on.
than stiff wall hoses. But the price paid is that flexible wall hoses can not be used for suction applications, like on the input to a water pump. Also flexible wall hoses want to straighten out when pressurized and so require more effort to aim a nozzle that stiff wall hoses. A pressurized 3" fire hose is very difficult to work and may require more than one person at the nozzle. Monitors (Wiki) are water nozzles that are anchored to avoid problems with the pressurized hose.
Stiff wall "Booster" fire hoses are typically mounted on a reel with a swivel fitting allowing them to be pressurized all the time. Just pull out and open nozzle when at the fire. These are very similar to garden hoses, except slightly larger in diameter.
The key advantages of flexible wall (fire) hoses is that they are lighter in weight, lower in cost and take much less storage space than stiff wall hoses. The early fire hoses were made only from fabric and so would degrade if left wet. This is why most fire stations have a tall hose drying tower. More modern fire hoses have linings that are not effected by long exposure to water and so don't need to be dried prior to being stored.
Note 1: This is the classic handline and requires training and strength to keep under control. Larger diameter lines are refereed to as supply lines, i.e. lines are are not moved once in place.
used on pressurized reels
Stiff Suction (pump inlet)
Stiff Suction (pump inlet) 12.6
Stiff Suction (pump inlet) 19.6
Stiff Suction (pump inlet) 28.3
5/8" & 3/4"
3/4" Garden hose Fitting
Flex Forestry 0.79
Flex Forestry 1.77
2.5" Note 1
Flex Heavy Duty - Supply line
Heavy Duty - Supply line 12.6
Flex Heavy Duty - Supply line 19.6
The early fire hoses were made of leather made much the same way that leather boots were made. Then came hemp fabric hoses that would leak water when first wet but after the fibers swelled would be water tight. These fabric hoses would be damaged if left wet and to fire houses needed drying racks to dry hoses.
More modern hoses have liners so that the fabric does not see water and so do not need drying racks. This also means these hoses are more suitable for home protection since they can be used for practice.
Water Pump (Wiki)
There are many types of pump, but a key property for a fire pump is self priming capability. This requires a positive displacement type pump that can generate a good vacuum on the input so as to suck water into it. (This really is just creating a vacuum so that the atmospheric air pressure can push the water into the pump. For fresh water with a density of 62 pounds per cubic foot or 0.43 PSI per foot of head and an atmospheric pressure of 14.7 PSI the maximum depth a pump can pull up water is about 34 feet.)
Also see Water Pressure.
The flow rate is determined by a number of things:The size of the meter
The size and adjustment of the pressure regulating valve
The size of the piping between the meter and the nozzle where the water enters the atmosphere
Elevation difference between the meter and outlet.
. . . .
In order to use exterior sprinklers where you can not use a line powered timer (the power probably will go out), it's necessary to have an adequate flow for all the sprinklers to run at the same time. At my house the water pressure at the street (fire hydrant) is 106 PSI and it's less than 10 feet of elevation below the house foundation elevation.
The size of the water meter limits the flow. Most houses have a 5/8" - 1/2" meter and the maximum flow is about 22 gallons per minute.
Table of flow rates for water meter size.
5/8" - 1/2"
common house meter
Pressure Reducing Valve (Wiki)
The hose bib just after the pressure regulator tests at 44 PSI with a Rain Bird P2A pressure gauge.
This hose bib will fill a 5 gallon bucket in 40 seconds. 5 * 40/60 = 7.5 Gallons Per Minute, and the pressure on the other bib is 20 PSI.
The water district says my water meter should flow 25 GPM at the meter. So the flow limitation is caused either by the 1/2" pipe or the pressure regulator.
There may be sprinklers that are tapped off the line between the meter and pressure regulator, need to test to see if that's the case. This would also explain why I've had so many problems with the irrigation system leaking. Two or three valves have failed in such a way that water leaks, in one case slow, and in another case the meter reader knocked on my door because the fast dial on my water meter was spinning very fast and had been for less than a month.
Water line coming from meter goes to pressure regulating valve then a "T" to the house and a hose bib. The hose bib has a "Y" with a battery powered timer and another hose bib (rather than use the "Y" ball valve).
PS I've had problems with leaking faucets inside and leaks at the unions here at the entrance. Here the plumber needed to redo some of the PVC fittings to (attempt) fixing the leak.
After waiting the normal time for the PVC glue to set up they opened the meter valve and the PVC fittings blew apart. The plumber said my water pressure was much higher than he expected (maybe 150 to 200 PSI).
I now think the pressure reducing valve is cutting down the flow from 22 GPM to 7.5 GPM, that's a lot!
For my case were there's a large pressure drop required to keep the pressure inside the house low enough that the appliances and fittings can handle it, more than one reducing valve may be needed. Note that the hose bibs are plumed from inside the house and to get good flow the whole house needs good flow. Also, if the hose bibs were connected before the pressure reducing valve then burst hoses would be the likely result.
Zurn-Wilkins 70XL water Pressure Reducing Valve (PRV).
There might be a relationship between the PRV size the the maximum flow you can get (based on Watts LF25AUB-Z3, LF is Lead Free, not Low Flow). But this is a function of the specific PRV.
Idea: "Reduced Pressure Drop", on the data sheet plot, varies from 0 PSI to 25 PSI for the Watts LF25AUB-Z3 and is the Y-axis scale on the Capacity plot. Flow (GPM) is the X-axis scale.1651237 Pressure regulator, Wilkins James M, Adolph Mueller, Nov 29, 1927, 137/327, 137/464, 137/328 -
I think this means that if you turn the adjusting nut all the way in and the water is shut off then the flow is zero.
All the wayout results in the maximum flow rate and corresponds to the highest output pressure. Then as you turn the valve back in the pressure drops and the flow goes down. But . . . the plots only show a "Reduced Pressure Drop"range of 0 to 25 PSI, meaning that for greater than a 25 PSI pressure drop more than one valve connected in series is needed to maintain the flow rate.
2519805 Pressure regulator valve, Wilkins James M, Aug 22, 1950, 137/505, 70/151.00R, 137/505.44, 210/432, 251/357, 137/549, 137/543.19 - adds strainer and removable mechanism without removing body from pipes.
2704551 Valve Mechanism , E.K. Ralston, Mar 22, 1955, 137/494, 200/83.00B, 137/505.44, 92/95, 251/337, 200/83.00P - uses Belleville washer (Wiki) in addition to the coil spring to get greatly improved GPM as pressure varies. In the PRVs that only use a coil spring the flow rate depends on the pressure drop.
Meter to House supply pipe
The flow through a pipe should be under 5 feet per second. At higher flow rates the friction loss goes way up, see Engineering Tool Box. This means I probably will need a new much larger pipe from the meter to my house.
It turns out that contrary to popular belief a key factor in the spread of fire is a storm of hot embers landing on something that acts as kindling. The hot embers will not start solid wood on fire. This explains the sight of a housing tract in the recent (October 2017) Santa Rosa fire where many houses, but not all of them, where burned to the ground. Yet this was a suburban housing tract, not a forest. That's to say it was not contact with fire that started the houses on fire but rather hot embers falling on dry leaves, pine needles or other kindling the flame from this then set something on fire, like a wood fence, which acted as a wick to the house. I say a storm because there's going to be thousands of these embers coming from the main fire and landing like rain down wind. If a house has nothing connected to the wood siding, like foundation planting, then even after the owners leave it may survive the ember storm without any outside help. Watch the videos in the box below so see how this works. There are many problems that need to be addressed, but a lot can be done to protect your house and out buildings.
The web pages of CCI (below) differentiate "Defensible Space" and the effect of embers. They are saying the "Defensible Space" on it's own is not adequate. I would agree. "Defensible Space" might be thought of a part of a plan to prevent ember fires and minimize flame front fires.
YouTube videos featuring Jack Cohen.
NFPA: Wildfire: Prevent Home Ignition: Part 1, Part 2 - firebrands (small hot embers) are the dangerous things, not the crown fire. The embers start things that act as kindling which in turn can start the house on fire. So, eliminating the kindling is key to preventing house ignitions.
NFPA: Your Home Can Survive a Wildfire (13:19)
NFPA: Firewise Virtual Workshop - Power of Embers (1:00:26) - http://firewise.org/ - Wind tunnel that can hold a full size house. Steve Quarles
Radiant Heat Versus Firebrands (embers) (3.33)
Protecting Your Home From Wildfire (28:51) Jack Cohen - examples of homes that burned and evaluation of homes that did not - details
Wildfire! Preventing Home Ignitions (19:26)
Fire Behavior in the Wildland/Urban Interface (21:07)
Fire dynamics (4:57) - smoke from heated wood is flammable
IBHS - IBHS Research Center Ember Storm Test Highlights (4:18) - Today Show - IBHS Research Center Ember Testing (2:55)- Insurance Institute for Business & Home Safety (IBHS) - has a wind tunnel with a bunch of NIST firebrand generators - "embers" Play List - Gable End Vents (louver type) and 1/4" screens let the firebrands through (YouTube)
NIST: Standard Firebrand Generator - used in wind tunnels for fire related testing - NIST Publications relating to Wildfires
Considerations For The Built Environment-Steve Quarles, PhD - The Landscape Industry's Role - Ed Smith - Ed's talk is about plants & embers - Living With Fire and Defensible Space - Ed Smith - Things that control wildfire behavior: Weather, Topography & Fuels
Living with Fire - the full version of the USGS film (22:44) - many scenes showing ember storms - "think from the house out"
Characterizing firebrand exposure during wildland urban interface fires, Ethan I.D. Foote (CalFire), 2011 - 90% of firebrands were less than 3/16". this is less than the common 1/4" (4/16") screen used to protect houses from rodents and pests. Updating to 1/8" metal screen would be good.
External Sprinkler Systems and Defensible Space: Lessons Learned from the Ham Lake Fire and Gunflint Trail.pdf
ConclusionPublicResource.Org - Using Water Effectively in the Wildland/Urban Interface - Portable Sprinklers -
Experience with the Ham Lake Fire in northeastern Minnesota demonstrated that external wildfire sprinkler systems can be highly effective at protecting structures and their surrounding vegetation from wildfire damage and destruction under certain conditions. Sprinkler systems are not a panacea however; they must be regularly tested and maintained, and even then, are not guaranteed to be 100% effective. When effective, there are several management challenges during wildfire events that still need to be addressed (e.g., getting property owners to evacuate when warranted and supplying propane to run the systems). Finally, Firewise principles and practices must be emphasized, with sprinkler systems as another tool on the Firewise list.
Note: the above comments are mainly about the propane powered water pumps which needed to be refueled and some did not start.
Garden Hose fitting to left.
Stake and foot step may be re-bar.
4' or 5' 1/2" iron water pipe and full circle 1/2" sprinkler.
The above information on hot embers suggests that 2" or 3" of rain fall has the effect of preventing ignition. It's not clear how since tall trees that were not directly whetted by the sprinklers did not burn. Maybe something to do with humidity. In the above references the exterior sprinkler systems used 3/4" impulse type sprinklers with a 3/16" nozzle. But these use a lot of water.
1/2" Brass Full Circle Impulse sprinkler Head
I'm looking into the Rain Bird 20JH 1/2" full circle sprinkler head (also 20A, 29JH?). It's a very simple design (reliable) and is used in high volumes for irrigation. It's also all metal construction which may be important for fire use in the case where the system is turned on after the heat/fire is nearby. They list for about $25 each, but supposed equivalents are made by other manufacturers for less than half the price, but it remains to be determined if they are as good for this application. Any plastic part would disqualify a sprinkler for this application if it's melting would in any way degrade the performance.
1997901 Water sprinkler, Orton H Englehart, Apr 16, 1935, 239/230, 239/259 -
This is the classic impulse or impact sprinkler.
65PJADJ-TNT - Brass Impact Sprinkler - this has a 1" inlet, 57' to 65' radius, 50 to 80 PSI line pressure, up to 1" per hour (I will need regulator just for these).
35ADJTNTB – ¾” Inlet Brass Impact Sprinkler - 3/4" inlet, maybe 30' radius
20JH 1/2" Inlet Full Circle Brass Impact Sprinklers - 1/2" inlet, 35 - 80 PSI, 35' to 44' radius (Full circle is much simpler, less to go wrong).
Underhill Product Code: SI100F Impact sprinkler - 1" Full Circle -
Manual valve and galvanized iron plumbing. Minimal plastic parts. Birds sitting on swing arm???? Freeze protection = drain valve
Report examines effectiveness of outdoor sprinkler systems during wildfires - External Sprinkler Systems and Defensible Space: Lessons Learned from the Ham Lake Fire and Gunflint Trail - "Experience was that with the cooler, moister environment created by the sprinklers, embers were suppressed before they were able to ignite the fuels, whether structures or vegetation. "
3/4" inlet heads with 3/6" nozzle
At least one 1-1/2" NH (National Hose) threaded Fire Department standpipe.
There is a question about "shelter in place".
Wildfire Sprinklers Inc. - full big $ systems
- Wildland Outdoor Sprinkler Information
- Sprinkler Spare Parts List
- Is a Wildfire Sprinkler System Right for You?
Rainbird Sprinkler Heads
Nelson Sprinkler Heads - Catalog (7 MB) - 1" & 1-1/4" inlets & much larger Big Guns - Brochure - 2", 3" or 4" inlets.
Nelson F33 (full circle) impact sprinkler head, 3/16 & 1/8" nozzles at 80 PSI: 13.25 GPM & 106' diameter. [The F33V the same except 113' diameter)FEMA Fire Sprinklers - Interior & Exterior
FlameGuard® CPVC Fire Sprinkler Products - some compatibility issues with non CPVC parts of the water system. Iron pipe may have a number of advantages for this application.
This is a generic phrase (Wiki) commonly used in active shooter situations, chemical spills &Etc. There is some talk of it's use in relation to Wildland Urban Interface (WUI) fires.
2001 Australasian Fire Authorities Council - Appendix H: Australasian Fire Authorities Council Paper - the beginning of the Shelter in Place idea.
2004 Preventing Wildland/Urban Interface Fire Disasters, Santa Rosa, CA, Ethan Foote -
"Houses protect people and people protect houses. Research conducted following major bushfires in Australia has concluded that the most buildings lost in bushfire situations are the result of initially small fires started by sparks and embers. A building will generally survive the initial passage of a fire front providing adequate preparations have been made. People who are well prepared and take shelter in their homes have an excellent chance of surviving a bushfire. Also, houses will survive if people remain to extinguish small fires started in and around them. "
2005 Homeland Security paper: Sheltering-In-Place During Wildfire, Is it a Viable Option? 2005
California Chaparral Institute - An Appeal to California’s Fire Agencies - "While creating defensible space is a critical component of fire risk reduction, it fails to address the main reason homes burn - embers landing on flammable materials in, on, or around the home, igniting the most dangerous concentration of fuel available, the house itself." ".... many homeowners have complied with defensible space regulations only to see their homes burn in a wildfire." - PROTECTING YOUR HOME FROM FIRE "Nearby vegetation was not a big factor in home destruction." - Fire Safe Techniques -
Akron Brass -Hardening Your Home - 32 Questions about your home and online assessment - Building Materials Listings - Search Listing Services: -
Booster Reels- Nozzles - YouTube -
Continental (Goodyear) - Water Hoses - Water Hoses -
eDarley - Darley - Wildland -
Eley / Rapid Reel Wall Mount Garden Hose Reel Model 1041 - Amazon - p/n 1044 Extra-Capacity Kit - 5/8"id X 175' Garden Hose -
Elkhart Brass - YouTube - NozzlesHannay - Booster Reels -
Firequip - YouTube (installing fittings on hose, kink resistance)
Honda - Water Pumps - WX (light weight), WT (trash), WH (High pressure), WMP (Multi Purpose), WSP (submersible)
Key Hose -
Kochek - Hoses -
Reelcraft - General Water Reels - 601044-150 3/4" x 150' Hose Assembly w/ Garden Hose Fittings, 300 psi - Amazon - GCCA33118 L 175' x 3/4" Reel - S601026-200 200'x3/4" hose -
1. Can the reel be mounted on the side of a house either directly or using an optional bracket?
2. Are the hose assemblies available with the correct male thread for connection to the reel and with a standard Garden Hose Thread male outside end?
3. On the motorized reels can the hose be pulled out by hand when there is a power failure?
R&R Fabrications - bags for many uses - Fire Hose -
Fyre-Tec™ Fire Rated Windows -
Steel Sliding Fire Windows -
Bandguard Vents -
Barricade Fire Blocking Gel - this has some problems: It must be applied immediately prior to the fire, i.e. you can not apply it a day or week ahead since once it dries out it's no longer effective. It is difficult to apply to all exposed faces, i.e. any surface irregularity will shadow a surface which is not protected. "Depending on weather conditions such as sunlight, wind and humidity, Barricade can be expected to last from a minimum of 6-8 hours to a maximum of 24-36 hours." Shelf life of concentrate is 4 Years if kept from freezing or getting above 120 deg F.
Video - Using Hand Tools to Suppress TN Forest Fires - Personnel Protective Equipment (PPE) & hand tools
While they say 1/4 to 1/8" metal vent screening - the testing I've seen says 1/8" metal is much better since it stops embers that might ignite some attic items.US Berkeley: Fire Information Engine - Homeowner Wildfire Assessment - an online report (but it has problems) - Center for Fire Research and Outreach at UC Berkeley -
It's interesting that the problem with embers escaping from a fireplace have been known for many years and my house came with screens on all chimneys.
Community Wildfire Hazard Assessment and Ranking -Homeland Security papers with "Wildfire" in title - search results -
Community Wildfire Hazard Assessment form.pdf
Builders Wildfire Mitigation Guide - tabs at top of page for various fire critical components
Under Codes & Standards:
California Building Code Chapter 7A
ASTM Committee E05
NFPA -NFPA - 1141 Fire Protection Infrastructure, 1143 Wildland Fire Management, 1144 Reducing Structure Ignition Hazards from Wildland Fire
ICC - Wildland-Urban Interface Code.pdf - the pdf is just the front pages ending with the table of contents
14 CA ADC § 1299.03 Requirements - Ref Link
Cal Fire list of links
Zone 1: from the building structure out 30 feet.
Zone 2: from 30 feet to 100 feet but not beyond the property line.
PRC68, Alphanumeric Index of Web pages, Contact, Products for Sale
Page Created 14 November 2017