Residential Fire Sprinkler System / Private Well Water

[dpwell]

Hello,

I'm the well drilling, pump and water conditioning contractor for an under construction private residence. The water is going to require an iron removal system and softener. The fire sprinkler system connection is already installed in the interior of the house walls and is fed off the house water supply. The minimum fire sprinkler system requirement is 32 GPM @ 39.6 PSI. There is going to be too much pressure loss through the conditioning equipment to feed the fire sprinkler system. The general contractor and the fire sprinkler contractor are unwilling to separate the two and provide an exterior isolated connection for the fire sprinkler system.

I'm thinking there is likely some way to solve the problem with an isolating by-pass valve, probably about 1 1/2 inch in size. I would set the well pressure system to turn on at 50 PSI and shut off at 70 PSI. The pumping system will have plenty of capacity to feed the fire sprinkler system. I will run two lines to the house, a 1 1/4 inch conditioned water for inside and a 1 1/2 inch unconditioned for the yard. I will tie the two together and provide separation with a valve. The pilot for the valve will be connected to the house water side. If there is a 5 to 10 PSI differential on that side (should only happen in the event of the fire sprinkler system being activated) the valve will open sending unconditioned water to feed the fire sprinkler system. I talked to my valve guys at the agriculture side of Bermad and they either can't or don't want to help. Does anybody know how to set this up or can recommend a valve supplier? Attached is a sketch of my perceived layout.

Thank you for taking the time to look at this.

 

[itsmoked]

I believe you should do it right and separately plumb it to the well. Nothing to go wrong, well runs - sprinklers work. Let the idiot general and sprinkler guys go pound sand. They made the bed sideways, let them pay for reworking it to clean up their cheap trick.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[dpwell]

I'm with you. I've been arguing with them since I first learned how the system was set up. I've scolded them both to the point that they don't even want to talk to me anymore. I told my customer to ask what they would charge to separate the lines and they are unresponsive. The general told her to take it up with the sprinkler contractor. I told her, what's the point of hiring a general then, their main purpose is to ride herd on their subs.

 

[itsmoked]

Wow dpwell I feel for you.. Sux.

I'm guessing the general never bothered to think about the home's water source or capability just plowed ahead as if it was on city water. Though, in my town on municipal water you're required to have completely separate services and meters for house and sprinkler circuits.

The inspector makes good points thinking about the reliability of the pressure/flow switch work-around. It is likely about 5% as dependable as compared to a direct line to the well. What; with a switch, valve, transformer, and required wiring. Since none of it will ever be tested in the future there really should be no expectation of it working in an emergency. This as compared to the direct connection which is inherently tested 10 to 30 times a day. Further more, who wants their potable water connected to a system where there are multiple dead-end stubs of stagnant water breeding who-knows-what all incubating in the warmest places of the house (attic and ceilings). Sheesh.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[dpwell]

I agree, with any system, the simpler the better.

The sprinkler line is purged by the toilets. The well has high manganese at 1 mg/l. If and when we connect it to the unconditioned water ony, the toilet bowls are going to turn dark brown without constant attention. I think the whole system is lame.

I have well drilling, electrical and water conditioning contractor's license classifications. Any work I do, I try to take into consideration how it will effect everything else, look at the big picture. It seems many others do not.

We're in California on the west side of the central valley. Our ground water here is prone to quality issues. The other contractors are from Fresno, closer the east side of the valley, their water quality is good. As you said they are used to connecting to municipal water supplies. They said they have done over 300 without a problem. I said, how about you don't do anymore over here.

Personally, I was disappointed when the whole residential fire suppression system requirement came about (at the height of the recession), but living here my entire life I understand this is a nanny state. I had no idea of the requirement on the first well system we installed after it came into effect. We barely eked by on the flow requirements. More than once after that I was the one that informed contractors (after they already bid the job) that fire sprinklers would be required. At my own residence I would prefer not to have them.

 

[itsmoked]

Ah, east side of the central valley.. Hi neighbor! I'm on the coast due west of you and up a few miles. I've been involved in controlling a lot of wells that need more than the usual filtering. Over here we have iron problem wells as well as manganese and even some arsenic ones. I've learned a lot about little gotchas that can cause us large headaches.

Purged-by-toilets... Sounds like a bad horror movie title.

If I were the homeowner I'd probably insist on a tank of at least 1k gallons and a pressure pump. Then the well can run continuously but infrequently. Also then when the well goes on the fritz you can have a day or three warning and even run from truck delivered water if needed. Makes life a whole lot less exciting. But I'm sure you know all that.

I just looked and in Santa Cruz county you are required to have 10,000 gallons on hand and a hydrant if you're not on municipal water.

Never thought about having to have sprinklers. Seems a good idea but would seem a better idea if they were dry systems.

Why do you appose them besides the flyswatter flood issue?

With the intermingled toilets, sprinklers, and potable it sounds like you might have to put in a greatly oversized filter system.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Valvecrazy]

I don't think coming straight off the well is an option. The 10,000 gallon tank is "mandatory". You will need to use water out of that tank on a daily basis to keep it fresh and clean. Now you could come directly off the booster pump, but without the solenoid the water treatment will need to be sized to handle the full 32 GPM.

I guess you could use an energize to close solenoid, which would make any power failure leave the valve in the open position.

What you really need is some more regulations and inspectors. I don't know how you can make this work without more help from the government.

How about this? Run the well pump directly to the water treatment and to the house. (would only need a small 10 GPM well pump) Tee off a line to the 10,000 gallon storage tank using a float switch and solenoid to refill the 10,000 gallon tank as needed. Could fill the tank with treated or non-treated water as desired. Have the 32 GPM booster pump teed into the main through a check valve and after the treatment system. With the well pump at 50/70, set the booster pump for 45/65. Then tee off the booster pump line prior to the check valve feeding the main line. On that tee off have a regular sprinkler valve and sprinkler controller. Once a week have the sprinkler controller open the solenoid valve and dump 32 GPM outside somewhere for 3-5 minutes. This will test the fire system and freshen the water in the storage tank once a week without running untreated water through the system. When actually needed, the system pressure will drop, opening the check valve and starting the booster pump.

 

[bimr]

Here's the county's response.

"Mike, Unfortunately I have 2 problems with your system. First the solenoid valve is not part of an approved Fire sprinkler system as per NFPA 13, Secondly who would be liable if the solenoid system failed?"

Based on the fire departments comments, I agree with itsmoked, the water line to the sprinklers will have to be separated. The silver lining for you is this removes the potential liability for designing and installing a work around system (valving etc.) should the system not work properly during a fire.

Another option that you may want to consider is reevaluating the sizing of the water treatment system and pressure loss. The maximum pressure drop through each treatment tank should be less than 10 psi. It is also possible to use conservatively sized equipment to reduce the pressure loss.

 

[dpwell]

The codes are published by the National Fire Protection Agency (NFPA). Everything should be standardized throughout the country. However it seems codes are subject to interpretation by jurisdiction and even by individual inspector. Here, in rural Merced County, the 10,000 gallon tank is required for commercial only and it is for the fire trucks to connect to. A holding tank is required for any fire sprinkler system that the well pump does not have the capacity to keep up with (this may come up in the Santa Cruz hills). This is when the booster pump comes into play. I think I've heard the size of the holding tank has to afford a twenty minute run time for the sprinklers. One engineer told me the size of the holding tank could be reduced taking into account the fill rate from the well pump.

Holding tanks and booster pumps add to the expense. The bypass valve would have also, but it would have been simpler, I believe more reliable (especially the pressure reducing valve) and more affordable. The in the wall sprinkler line connection may be common in Fresno and Madera counties. Over here in the sticks our inspector said he'd never heard of it. He's fine with the sprinkler separated and outside the exterior wall. That is the simplest, least costly (at least on my part), and most reliable solution. I think tearing out the wall, replumbing the sprinkler lines and patching the damage shouldn't cost more that a couple of thousand dollars.

I could have put the bypass valve and not told the fire inspector, he wouldn't have understood what was going on. I could have switched the conditioning equipment to by-pass during the flow test or installed it after the fact. I wouldn't do any of this due to the liability issues. I've been straight up with the inspector because I want his consent, in writing. I wonder how often water conditioning equipment is going to be installed on houses plumbed like this without anyone realizing they have defeated the fire sprinklers.

The biggest problem is the greensand iron removal system, it would have to be huge. Conditioning equipment sized to meet the flow requirements is not practical. I could explain it all, but you would get bored. I will if you want.

 

[itsmoked]

Ah yes green sand iron removal. You certainly don't want that any bigger than you need. Backwashing a large filter would take another pump and probably a storage tank to provide the correctly fluidized bed. I did a 50gal/min system but we had 1/4Mgal tank on 250ft hill to provide the backwash umph. That filter was five feet in diameter and 7 feet tall. But wait, that was an arsenic removal job and you actually have to inject iron into the water so that filter had to be even larger. How big is the sand filter for this job without the sprinklers?

I commend your above-board reasoning and concur. The house builder and sprinkler guys need to do what's right. Hopefully you can get the fire inspector to mandate separation in this case. Sadly this was a situation where whatever govment lackey approved the plans should've understood this and red-lined the lunatic mixing of domestic and fire.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[dpwell]

Perhaps a 1 1/2 cubic feet with a 12 inch diameter vessel and 5810 Fleck valve.

The cross section of the greensand to meet the flow requirements of the fire sprinkler is 8 square feet. A 42 inch diameter tank is 9 square feet and as you said, we can't backwash it. We would have to use multiple filters plumbed in parallel. Upon realizing this we gave up on that approach.

 

[itsmoked]

Thanks for that. Scratched my itch.

Well, please let us know what transpires.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Valvecrazy]

Even if you separate the domestic and fire flow, you still have to fill a storage tank and maintain a booster pump. My idea from above will work no matter if you separate the fire flow or not. You still have to exercise the pump and freshen the water in the storage tank. I will repeat it here.

How about this? Run the well pump directly to the water treatment and to the house. (would only need a small 10 GPM well pump) Tee off a line to the 10,000 gallon storage tank using a float switch and solenoid to refill the 10,000 gallon tank as needed. Could fill the tank with treated or non-treated water as desired. Have the 32 GPM booster pump teed into the main through a check valve and after the treatment system. With the well pump at 50/70, set the booster pump for 45/65. Then tee off the booster pump line prior to the check valve feeding the main line. On that tee off have a regular sprinkler valve and sprinkler controller. Once a week have the sprinkler controller open the solenoid valve and dump 32 GPM outside somewhere for 3-5 minutes. This will test the fire system and freshen the water in the storage tank once a week without running untreated water through the system.

 

[itsmoked]

Valve; I think you keep missing the fact that there will not be a water tank.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Valvecrazy]

"A holding tank is required for any fire sprinkler system that the well pump does not have the capacity to keep up with (this may come up in the Santa Cruz hills)."

Yep missed that completely. Now as long as the well can make 32 GPM all you need is to figure out how to control the well pump. It will need to produce 32 GPM at 60+ PSI when needed, as well as run safely and dependably for a 3 GPM shower in the house.

 

[dpwell]

We finished our part of the job today. We stubbed up a 1 1/2 inch unconditioned water pipe in the vicinity of the conditioned house water connection. The fire sprinkler contractor is supposed to tear out sheet rock, separate the lines and connect the fire sprinklers to our stub up, tomorrow on Friday the 13th. The fire sprinkler requirement is supposed to be 32 GPM @ 39.6 PSI. Always in the past, we performed the flow test at the well head. The fire sprinkler contractor said the test was done in the garage (which is the opposite end of the house from our 1 1/2 inch stub up). The house water connection is 1 1/4 inch. The house is plumbed with PEX. There is an orange PVC connector with 3/4 female brass threads next to our stub up. They said it was a flush port or something. The pump is 35 GPM and we wanted to use a 1 1/2 HP because it best fits the application. We flow tested another we had recently installed with similar water level conditions. It did 39.4, 35.6, 30 and 25 GPM @ 40, 45, 50 and 60 PSI respectively. If the flow test was done at the well it would have been fine. If it was done at the house (passing through 110 feet of 1 1/2 pipe it still would have been okay. Since I have now idea what is going on with the sprinkler plumbing in the house, we went with the oversized 2 HP unit. We left the pressure setting at our standard 40- 60 PSI. This pump will probably cycle with the fire sprinklers running. We'll go by Monday and see what (if anything) the sprinkler contractor did.

 

[itsmoked]

Finally. The correct solution. Yay.

What got them to actually correct things appropriately?

Clean pad/site. Can't really tell by the picture, are you using the pressure tank directly on the unconditioned water?

What are you doing with the backwash water?

Is the filter controller one of those electromechanical water-softener type gizmos?

If it is, are you satisfied with their performance?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[dpwell]

I told the customer there was nothing else I could do after the county shot down the bypass valve plan. She got them to agree to re-plumbing their system (we'll see what they actually do).

The pressure system plumbing design follows my age old basic system design, but adds a tee to branch towards the water conditioning equipment (to the left in this case). The iron removal system is spaced further from the tank because the water softener would go in that slot. I set them up like that because many systems don't have iron removal and that keeps the softener in the same position regardless. The water always goes to the iron removal system first. This location will almost certainly get a softener in the future. It is a speculation house (in escrow) and the seller won't pay for the softener. When we talk to the buyer we will tell them a well house is highly recommended.

The backwash water will spill on the ground directly in front of the well slab. We recommend attaching a short hose and moving it around on the grass from time to time. We look for somewhere to dump the drain water. In this case there is a small irrigation ditch about a 100 feet away. We would set up an air gap and let gravity take the waste water away. Due to set back requirement the septic tank is difficult and would probably require a sump and pump to get it there. We have also considered a French drain, but wouldn't want to upset environmental health, so we would have to wait until all well inspections were complete. In this situation the expected buyers are in the "earth" business so they may deal with the drain issue themselves in one of the ways I've mentioned. We will try to impress upon them the importance of backflow prevention.

The filter is controlled by Fleck's SXT programmable system. We stayed with mechanical valves for a several years after they came out. The new higher flow inexpensive (comparatively speaking) residential valves are exclusively programmable controls. We have a few old school valves in our inventory, but these days we only purchase the modern valves for stock. They seem to be as reliable or even more so than their predecessors. We don't know how they will compare longevity wise yet. We do keep a couple of spare printed circuit boards on hand as we have observed them fail, although not very often. I would recommend purchasing the new valves over the old style at this point.