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We would be delighted to try and obtain an answer to any questions you might have regarding fire hydrants, whether of a technical or general nature. Below are recent questions and answers from the mailbag. If you have a question, Email Us.
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  • #1 - Can anyone advise the NFPA code which specifies the spacing of fire hydrants? This is for a co-generation plant in Illinois. Thanks.

    According to the standards, the final authority for hydrant placement is the local agency "Fire Chief" or his/her designate. State and local codes and ordinances may also apply.

    In general, spacing is based on a few factors. A sufficient number of hydrants have to be immediately available to provide the required fire flow for the structure(s) protected. Rule of thumb for this is that each hydrant being considered should be within 500 ft (hose laying distance) from any portion of the structure being rated. Credit may be given to hydrants farther than 500 ft. away however in most cases only partial credit is given, depending on the distance, up to a maximum of 1000 ft.

    If the local fire agency carries large diameter hose LDH on *every* front line engine which is accredited by the Insurance Services Office (ISO), then full flow credit will be given all hydrants that are within reach of the smallest LDH hose load that the fire agency has, up to 1000 ft.

    For example,

    Fire mains will provide 5,000 GPM. Required fire flow is 4,500 GPM. Each hydrant will provide 1,500 GPM. 3 hydrants have to be in proximity to the building, the location to be decided by the Fire Chief (for operational reasons.) If the local fire department does not have LDH on all accredited engines, they should all be within 500 ft. of the building. If the smallest LDH hose load carried on any "front line" engine is 900 ft., then hydrants up to 900 ft. away will be considered.

    As one can see, the developer and the Fire Chief need to sit down with a site map and fire flow calculations to determine how many hydrants are needed and where the most appropriate locations for them would be.


    "Reserve" apparatus doesn't have to be equipped with LDH to meet this standard provided they are not part of the basic first alarm response compliment to a structure fire in the building being considered.

    In large developments where mains are being installed but buildings are presently not planned, and where the developer wants to go ahead and install the hydrants while the trenches are open to save total costs, a really good rule of thumb is to place the hydrants at 500 ft. intervals.

    ":O) Willis Lamm,
    Captain / Water Supply Officer Moraga-Orinda FD

    #2 - I am an assistant project manager on a commercial office building that has a unique hydrant issue. The county is requiring us to install an additional hydrant after construction is substantially complete, and the proposed hydrant line will run through an area designated as a future data center, an area for computer storage. The line would enter the area horizontally below slab on grade and turn vertically 15 feet up through the data center to the deck above.

    As the developer / constructor, our intent is to keep all water lines out of this area in order to provide an attractive, risk-free data center for future tenants. Having the hydrant line running in the area would compromise the integrity of the area. I am researching the possibility of making the hydrant line some type of dry system that would only contain water when the hydrant is open, similar to a dry fire extinguisher system.

    Any information or suggestions you might have would be greatly appreciated.

    Here are my thoughts on this.

    First off, if the hydrant is on a deck, is it realistic that a fire engine would actually hook up to it and take water? If not, you might propose a standpipe system for direct use by fire hoses that could be supplied by a fire department pumper. The Fire Department Connection could be placed adjacent to some other fire hydrant in the yard that is convenient.

    If the hydrant is required to meet statutory fire flow requirements, an alternative could be to locate an additional hydrant and the standpipe FDC at some location on the facility that meets code but doesn't compromise the slab.

    A good argument in your favor is that it would be impossible to properly maintain a hydrant lateral run 15 feet below an occupied slab, so you and the Fire Marshal should identify a reasonable alternative system as provided for in the Uniform Fire Code.

    As a fire service professional, I don't like hydrants placed on decks or too close to buildings. It places the pumping apparatus at risk. I prefer hydrants placed a safe distance away and distances made up by standpipes near doorways and other points of access where hoses can be connected and utilized. Furthermore, if the fire is significant and aerial streams are required, I want the hydrants in locations where I can quickly and efficiently supply my ladder trucks which need to be some distance away from the building.

    If you're still stuck on this, you might ask the Operations Chief of the Fire Department over to look over the site and suggest how he would fight various fires in the facility and what resources he would need built in to do so. You get his endorsement for an alternate plan and you stand a good chance of avoiding the slab installation.

    Hope this information helps.

    ":O) Willis Lamm,
    Captain / Water Supply Officer Moraga-Orinda FD

    #3 - This is quite urgent. I am buying a new townhome and there is a fire hydrant blocking half of my driveway. I have a one car garage and a driveway that is wide enough for two cars. But the developer has placed a fire hydrant in the swale directly in front of the second parking space and they say it is impossible to move a fire hydrant once it has been placed. It was put there before construction began. Please give me the feasibility of relocating the hydrant either 6 ft to one side or across the street to a small park. Our closing on the new townhouse was supposed to take place today, but we do not want to accept that the fire hydrant simply cannot be moved. We only have one more week before we are out on the street. Thank you so much for your information.

    Depending on the type of hydrant and other factors it can cost between $1,500 and $5,000 to relocate a hydrant. Killing the original tap and boring a new tap onto the main is the best way from an engineering standpoint but is the most expensive approach. The most logical approach would be to move the hydrant bury to the proper location, then attach it to the original branch line via a wide bend elbow. The materials costs would not be extreme but a section of the sidewalk and pavement would have to be replaced.

    If I was the buyer I would check on the conditions of approval for the subdivision. If they call for 2 car driveways and garages, I would send the master contractor a letter complaining of defective design. (Your 2-car driveway doesn't work and the location of the hydrant is a safety hazard.) If he fails to respond, then I would get a relocation estimate from the water agency and/or the plumbing contractor that installed the hydrant and present it in small claims court.

    ":O) Willis Lamm,
    Captain / Water Supply Officer Moraga-Orinda FD

    #4 - Could somebody from the industry (either distributor, manufacturer or purchaser) please explain to me the process behind how cities/municipalities/water utilities go about getting fire hydrants? Do they frequently post such things as tenders and if so where are they posted? Who fills the orders? Manufacturers or distributors?

    I now work for a municipal water utility, but worked in the purchasing department before getting a life on the operations side.

    Typically, in a public purchasing environment, major purchases have to be open to competitive bidding. This is a double edged sword because you can end up with good prices, but also a real smorgasbord of manufacturers. This creates problems operationally because you need parts to service your equipment, but must manage your investment in inventory.

    What you have to do is a bit of a balancing act. You need to limit the variety of hydrants you will accept without compromising the competitive bidding process. You have to take into account your current inventory of installed hydrants, specifications (AWWA,UL,FM, etc..), maintenance history, and availability. We have limited our approval to three current (3) models.

    Tenders are normally advertised in local newspapers, but many levels of government are now posting tenders on their websites.

    Manufacturers normally distribute their products through authorized distributors unless there isn't a vendor in your area.

    Hope this helps.


    John Clack
    Saint John, New Brunswick

    #5 - I have a developer proposing to install two hydrants located on the property in a "y" configuration. Both hydrants will be dead end off the single source. An 8" feeding a wye with a 6" feeding on hydrant off the wye and a 8" feeding the other half of the wye. And off the 6" leg comes the fire protection line and service line to the building.

    So, my question is....Any codes to force him to loop the system or does the code only require specific flows and pressures. I cannot imagine why he wants to do this, yet I have to come up with the reason as to not allow it. - Deputy Fire Marshall

    UFC 903.2 requires "An approved water supply capable of supplying the required fire flow for fire protection shall be provided..." It seems odd to me that the 8" leg only serves one hydrant while the 6" leg serves the fire protection and service lines in addition to a hydrant.

    Since each leg is serving only one hydrant, a dead end is probably adequate although we all recognize that looped systems are more stable. I would question why all the services are off the 6" leg unless it is intended that the 8" leg be extended at some future date and not the 6" leg.

    Flow capacity through each leg would depend greatly on gradient and the stability of the feeder main. If the 6" leg will support domestic consumption plus required maximum fire service consumption (standpipes and sprinklers) plus required hydrant fire flow at 20 psi residual, then the wye concept is probably OK. Bottom line is that in most jurisdictions, the final decision is up to the Fire Chief or the Chief's designate. (903.2 further states, "on-site fire hydrants and mains capable of supplying the required fire flow shall be provided when required by the chief.") If the Chief or Fire Marshal has done the calcs and is happy with the results, so be it.

    Just remember to consider the aggregate potential flows when determining the fire flow requirements and if simultaneous flows from both hydrants plus private fire systems are required to meet the building's fire flow requirements, then calcs should take in to account the conditions in those mains when both legs are delivering their aggregate requirements.

    ":O) Willis Lamm,
    Captain / Water Supply Officer Moraga-Orinda FD

    #6 - "We have been testing every hydrant in our district for the past 15 years. The problem is they grow in numbers every year and we want to know if we need to flow test every hydrant? Can we test a % of hydrants? Can we test a % on a given main? Testing every hydrant is becoming a huge job."

    We can't flow test every hydrant every year.

    While opinions may vary among ISO inspectors, we get full compliance by inspecting every hydrant each year (which includes making sure that the valves open) and we try to actually flow test about 1/3 of the hydrants each year. Really solid zones probably get tested about every 5 years while weaker or critical areas get tested more often. The critical issue is that the hydrants operate. Of secondary importance is the issue as to whether flows are declining since, except for street valves which are closed for maintenance and not fully reopened, declining flows are usually a process which occur over many years.

    See the section on hydrant inspections:

    ":O) Willis Lamm,
    Captain / Water Supply Officer Moraga-Orinda FD

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