What's The Service Life of Fire Hydrant?

I have never seen a crew replacing a fire hydrant. I assume that they are made of cast iron, and are extremely sturdy.
So, other than being hit by a car or snowplow, do these things have an indefinite life?
The design of them probably hasn’t changed in years-so is it likely that my town has some hydrants installed, say, 100 years ago?

Here is a model of afire hydrant that was patented in 1869. This hydrant may not be that old, as designs were used for many years, but certainly it is 100 years old and still in service.

Good question. All the ones in my subdivision are dated between 1969-1975, the time the area was built.

I guess they last a long time.

I read that 100 years for the cast iron ones, except for the ones that get knocked over by cars.

I have some on my site from the '50s. It’s not the cast iron that goes bad, but the gaskets and seals in the valves. Some of mine, I can’t find replacement parts for, and it’s cheaper to just replace the whole hydrant.

There are collectors for some of the older ones. When I pull a Greenburg, I’ll try to get in contact with one of them.

I worked at public works for my small hometown, many years ago. Most of the hydrants I would say were put in in the 1960’s, and they do tend to last a long time. We did replace about half a dozen or so every summer, though. Along with the ones that got knocked over by cars and so on, a number of them were broken by the fire department as they tested them every now and again. As Cowgirl Jules explains, it’s usually just easier to replace them than to fix stripped valves and whatnot. They don’t last forever, but they tend to not get broken except when they’re being used, that is, they tend to not spontaneously spring leaks and things like that.

There is one in front of my house. It was replaced in '03 or '04. The previous one was leaky for years until the City got around to it. If it was the original one, it was installed in 1960 or '61.

Aside from the one up the street, which has been hit a dozen times in three or four years, I have reported one fire hydrant that was leaking. The city were digging it up the next day, put a patch on the waterline where it had broken checked the hydrant (nothing was wrong with it) and filled in the hole.

I have personally used hydrants manufactured and installed in the 1910s without a problem. I have also broken a hydrant manufactured in 2003.

The majoritiy of the hydrants in my town are from the late 1950s up to the mid 1960s (Kennedy hydrants). There was a time in the 1980s that the hydrants were not well maintained, or even touched for that matter. The nozzle caps are cast iron, most corroded themselves to the threads on the nozzles. Even today, we still suffer from caps being seized to the hydrant. It’s most prevalant on the 4-1/2 inch “steamer” port on the front of the hydrant. The only way to remove the cap is to hit opposite sides with small sledge hammers and fracture the cap off. Just make sure you don’t hit too hard and deform the threads, lest the hydrant become useless. The new hydrants we have are Muellers, the water district claims they are easier to maintain than the Kennedys were, but they don’t stand up to abuse as well. I can’t vouch for that statement, they all work the same to me.

I have also broken my share of hydrant stems. There is a shaft that goes down through the center of the hydrant’s barrel to operate the valve at the bottom (a dry barrel hydrant sits on a vertical pipe going 6+ feet below ground - the valve sits at the bottom of that pipe). If the valve at the bottom isn’t functioning properly, and you over-torque the operating nut at the top, the stem snaps and the hydrant is useless.

The last failure I’ve seen wasn’t my fault, someone else opened the hydrant. There is a drain at the bottom of a dry barrel hydrant that lets the water out of the hydrant so it doesn’t freeze. The drain automatically closes when you open the operating nut, it usually takes about 6 to 10 turns of the nut to get the drain to close at the bottom. A hydrant takes about 28-32 turns of the operating nut to fully open. This one hydrant was fully opened, but the drain didn’t close. The force of the water pushing out of the drain (full street pressure) undermined the soil around the hydrant, turning it into muck, and allowed the sidewalk and street around the hydrant to collapse into the hole. Ugly, ugly day.

I have also heard about hydrants that are knocked over by vehicles being put back on their mounting flange by the driver. If you drive into a dry barrel hydrant, the stem breaks and leaves the valve at the bottom closed. There should not be a Three Stooges-style geyser from a dry barrel hydrant that gets hit by a car. I have heard of hydrants hit that fell over, but no water came gushing out, so the driver manages to stand the hydrant back up on the pipe from whence it came and takes off. When the first firefighter that tries to open the hydrant turns the operating nut, the hydrant falls over. Another way to ruin your day. I have never personally seen it happen, but I have heard about it more than once. Read about it, too. I’ll accept that it happens.

Like many simple mechanical devices, if hydrants are maintained properly, they’ll last forever. If you abuse them, they’ll break the first time you really need them.

So, just for curiosity, what is involved in “maintained properly”?

Do you go out once every year or two to each hydrant and turn it on & off to keep the valves moveable? Do they need to be oiled? Do you wash them off? And how often do they have to be painted?

I try to flush mine twice a year. That gets sediment out of the main serving it and exercises the valves of the hydrant itself. I like to put a food-safe grease on the threads of each cap so they don’t seize up. I clean up the vegetation around them at least yearly.

And I really need to sandblast and paint some of them, but my client hasn’t come up with the money for that yet. Some have way too many layers of paint and are peeling, and some just have one layer and it’s wearing off. Plus, there are new regulations on the colors the caps are to be painted, related to the fire flow the hydrant puts out, and I need to get into compliance with that.

With regards to the ones with bad valves, mostly I just have a list of those to be replaced. Again, when the money comes around, which will probably be a while.

  • Most hydrants (particularly the Muellers linked above) have a zerk fitting either on the bonnet (the rounded top of the hydrant) or recessed in the operating nut. That lubricates the bearing/threads at the top of the stem.
  • Opening the hydrant once a year exercises the main valve and the drain at the bottom of the hydrant, plus it makes sure that any stones or beer cans aren’t sitting at the bottom of the hydrant barrel.
  • Remove all of the caps, dab some white lithium grease on the threads, and reattach them.
  • When they look like the paint is starting to peel (every three to five years around here), scrape/wire brush and repaint them.
  • In northern climes, some places will do hydrant flushing and flow tests in October/November, just before the freezing season starts. If you do it then, you can make sure the hydrants are draining or are full of water so they can be manually pumped down (frozen hydrants = broken hydrants).

Not including painting, it takes about 5 minutes to service a hydrant. If you have to paint it, it obviously takes longer depending on how much prep work needs to be done.

What do you mean by “mine”?

From this and your other post, it is clear that you are a firefighter of some sort. But from this, it sounds like you rank pretty high up there, or perhaps you are the entire department unto yourself.

Not trying to pry, I’m just curious.

No, I’m a water distribution operator. I run a small enough system that I’m both in charge and the flunky turning the valves.

In some systems, the firefighters do indeed do the maintenance on the hydrants, but in about half or more of them, it’s the water distribution operators doing it. The hydrants are also used for water main maintenance, not just firefighting purposes, so it can really go either way on who takes care of them.

Hydrants are remarkably sturdy. I ran into one cutting across a vacant lot and bent the axle of a pickup truck that way. Hey I was 16 and stupid, alright? Alright.

My department flushes the system twice a year, and performs inspection/pressure testing annually, but we do not do any outright maintenance on the hydrants.

ETA: the oogiest thing that happened while flushing hydrants for me was the time I opened one up to find a colony of fire ants inside. I flushed that one extra long…

Oooh, yuck! About two-thirds of mine are wet-barrel hydrants, so no ants actually in them. I could see them getting into a dry-barrel though. Mostly I get wasps living under the edges of the caps.

I also take my .357 loaded with shot in case I find a copperhead. Hasn’t happened to me personally, but there is a great fire story of another active member that did…

Wow, the things I learn here!