1-3/4 Hose Vs. 1-1/2 For fire attack

[jpowers]

I have recently been appointed to head a committee to determine if 1-3/4 hose should replace the 1-1/2 hose already in service. I feel that it would be an asset to the department, but the union feels that it is to heavy and that 1-1/2 hose is sufficient for our purpose. Please forward your feelings on both types of hose.

[hwoods]

Sorry, I couldn't pass that up, we've visited this topic any number of times. We use 1" for grass fires, 1-1/2' for Autos, Structures Etc. We back up the 1-1/2" with a 2" line on Structures. 3" is our supply line, and we've been known to place a 3" handline in service when needed. In my opinion, you should (if you don't have any now, get a few hundred feet) put a 13/4 line on an engine and try it for a period of time, see what works best for your department.

[Rayr49]

I agree. Try a couple of 1 3/4" lines. Both my career and volly depts have used the 1 3/4" with 1 1/2" couplings for quite a few years. The weight difference is small but you gain in friction loss and volume that can be delivered.

The big problem with making the switch is training your engineers and you attack crews on its use. We use TFT variable gallonage nozzles. I can start with a preprogramed engine pressure to flow 125 GPM. I can increase flow into the 150-175 GPM range if the attack crew and the engineer are both on the same page.

The 1 3/4" line does not replace 2" and larger lines when you need big flow. This has been another problem of developing "tunnel" vision and deploying the 1 3/4" when a 2 1/2" should have been used.

Stay Safe
IACOJ

[Adze39]

Originally posted by Rayr49
The weight difference is small but you gain in friction loss and volume that can be delivered.

That's the big one!

Let's look at a 100 psi nozzle flowing 150gpm through 200 ft of hose:

Friction Loss (FL) on a 1.5": 108 psi
Pump Discharge Pressure (PDP): 208 psi

FL on a 1.75": 70 psi
PDP: 170 psi (unless you're using a Elkhart w/ "One for One Hydraulics", then it would only be 150 psi)

The same arguement can be used for going from 1.75" to 2"
I know of some departments in Eastern CT that use 2"
FL on a 2": 36 psi
PDP" 136 psi

For the 208psi pressure in the 1.5", you can get the following flows:
1.75": 187 gpm
2": 260 gpm

--------------------

We use 1.75" with a 2.5" as the "big line"

[SafetyPro]

We use 1 3/4" as our primary attack line. Each of our engines has a bow line, two cross-lays and s rear pre-connect of 1 3/4". We also carry a rear pre-connect of 2 1/2".

The only 1 1/2" we use is in our brush-packs.

[SFDchief]

I think the last time I've seen a 1 1/2" around here was some 15 yrs ago. That was when we completely switched to 1 3/4 because of the advatages that we felt out weigh the minor disadvantages. At that time, each engine carried (3) 1 3/4" mattys.

Now present day this is no longer the case. Now we still have 2 of the 1 3/4 inch matty's (200' each), along with a 1 3/4 trash line (50 feet) and a 100' 1 3/4" highrise pack BUT, we replaced one of the mattys with a 2" line (200 feet) with a sb nozzle (no comments on sb vs fog, been there, done that). All of the above have 1 1/2 couplings.

To go along with the above, We carry 250 feet of 2 1/2" for a manned master stream along with 500 feet of 3" for a portable monitor setup and 1000' of 5" LDH.

When we first got the 2 inch several years ago, there were people hesitant on using it (heavier, difficult to manuver, etc.). Now, 9 times out of 10, it's the first line pulled into a structure because of the increased gallonage, operable at less pressure with the sb and less friction loss.

I would definately recomend the switch. For most departments around here 1 1/2" is a thing of the past.

[Dalmatian90]

I like 1-1/2".

Use it with good size-up and (gasp) common sense.

200' 1-1/2" will flow 95-125gpm, and in most situations be more than enough hose for single family dwellings. For a fire of unknown location (we have moderate smoke, no fire showing...) or partitions, it's a quick line to work and move. More than enough for a reasonable room & contents (like a bedroom) that's vented, and especially with bedrooms going upstairs or down halls it's nice to have the lighter line. Yes, I notice and I'm a big guy.

Thinking basement fire, seeing a "big" room & contents like a kitchen extending to hall/living room, yep, grab the 1-3/4". I guess that's being conservative, I have & know the 1-1/2" can knock down multiple rooms (I've done 3+ rooms with an 1-1/2" several times). But the 150-200gpm flows give you a "margin."

Problem is a lot of people like to go to the high-flows, and in the extra hose weight, extra nozzle reaction, being "scared" into thinking a fire is something to always fight with heavy weaponery, they get less mobile and nozzle work suffers.

Putting out fires is about sucking up BTUs, and sucking up BTUs isn't about how much water you can or do flow -- it's how many gpm you actually apply to things that are burning. 1-1/2" lines are just easier to do that with, and a good crew with that line is much more effective than a crew that's being timid with an 1-3/4" or a crew that's having to stop, brace themselves, open up the 1-3/4", darken down, then move -- 1-1/2" is a lot easier to move & flow, and even if you hold for a moment to darken down it's a lot easier move forward and be "aggressive."

I've never been one to buy into the smoothbore/low pressure lines being easier than fog/high pressure lines -- I don't find 150 or 200psi on an 1-1/2" unmanageable, or even an 1-3/4". But I do find the weight and lower nozzle reaction (yes, from lower flows) to be easier on the 1-1/2"...and that lets me be more aggressive.

I guess if I had my "ideal" world, we'd run an 1-1/2" as a "Utility" line to use on 90% of your outdoor fires, small room & contents, partition fires, etc, and 2" as the line when you're not confident the 1-1/2" has the punch. If you're gonna go with more a set & hit work like 1-3/4" tends to encourage, might as well hit it with an even bigger flow. Jeepers, hwoods, maybe I need to move down there although I'd insist on bringing along my 5". (Laid 1500' of that at a drill this morning )

[SFDchief]

Originally posted by Dalmatian90
I like 1-1/2".

Use it with good size-up and (gasp) common sense.

Common sense, the lost art

[ndvfdjrff]

All preconnects on our trucks are 1 3/4's.....We rarely ever use 1 1/2

[Weruj1]

we too use 1 3/4 and 2.5 attack lines ...........it certainly isnt that much heavier ...........I wonder what 2 inch line would be like ?

[OFD226]

Our department just underwent a major transition from ALL 1 1/2 to 1 3/4 and 2 1/2 with smoothbores and low pressure fogs. PM me if you want more information on this subject. We are a large department that runs alot of fires, so I can let you know about the transition and adjustments that are the reality on a fireground

[firenresq77]

We phased out all of our 1.5 a long time ago and use the 1.75 and 2.5 lines. I would like to try the 2" one of these days. Would also like to see some SB's to try out, but it's a matter of getting the powers that be to let us get a couple.....

[FyredUp]

Not to sound like an old guy or anything but in my time as a volly here we have gone from 1 inch boosters to 1 1/2 inch to 1 3/4 inch to now 2 inch. Flow was the reason.

We are now an FD that uses 1" forestry hose for brush fires, 2 inch for all other fire attack, 3 inch for water supply and feeding our preconnected rear step stinger, and 5 inch for water supply. The only remaining length 1 3/4" line we have left is a 100 foot trash line.

We expereimented with 2 inch several years back and found the FF's passing the crosslays and going to the 2 inch anytime we had a working fire. The then chief decided to go all 2 inch. We put 200 gpm at 75 psi nozzles with a 1 1/4" slug tip on them. We underpump initially to flow around 160 gpm, we can go to 200 with the combination tip or spin that off and flow 300 gpm at 40 psi at the tip. The benefit? You never grab the wrong line. As far as the weight of the line goes, we regularly move it with 2 FF's because like most everyone else there is never enough help in the first few minutes.

Back to the 1 3/4 versus 1 1/2 inch lines...the weight is no big deal and flow is much better.

FyredUp

[CALFFBOU]

To quote and old Fire Service Instructor- "A while back
the fire hose industry was stagnant so they came out
with 1 3/4 hose."

You know what, I believe him. I had been using 1.5 line
and never had a problem with it. I liked the manuverability
and light weight. My FD now uses 1 3/4 and I dont mind it
but you might have some resistance moving around a house.

A wise old crusty FireMAN once told me- "If youre a smart
nozzleman, you can put out a lot of fire with a little
water."

You know what, he was right too! I have since practiced
what he told me and again with that in mind, the 1.5 works
just fine for me.

-Bou

PS- See OFD226, even I can be a little "old skool."

[FireH2O]

Addressing the weight difference between hoses:

The difference in the weight of the water in 50 feet of hose can be calculated from the following:

WD = C (D^2 - d^2)

WD = Weight Difference of the water per 50 feet
C = Constant (Temperature dependent)
D = Diameter of the larger hose
d = diameter of the smaller hose
^2 = Square

Although the temperature will make a difference, it is minimal.
C = 17.025 for 40 F
C = 16.968 for 80 F
I suggest using C = 17.

The weight difference between 1-1/2" and 1-3/4" varies from 1 pound per 50 feet to 4 pounds per 50 feet depending on the manufacturer and model.

The difference between the 2 hoses for 200 ft would be approximately 55 pounds (water weight) plus 4 to 16 pounds hose weight). Use 60 to 70 pounds. This assumes the inside diameter of 1-3/4" hose is 1.75" and 1-1/2" hose is 1.5". I think the actual inside diameter may be larger (particularly under pressure).

I know one department that converted to 1-3/4" hose and then decided it was too difficut to maneuver so convert back to 1-1/2".

[CALFFBOU]

Originally posted by FireH2O
I know one department that converted to 1-3/4" hose and then decided it was too difficut to maneuver so convert back to 1-1/2".

Brother- I believe that one.

[firespec35]

If you can't use 1 3/4" hose for your "standard hose" then what are you doing in the fire service? I'm an out of shape fatso and I still can haul 1 3/4" around w/o a problem. We even are taught to control our water for our car fires out here so the engineers can get a good look at the true cause of the fire.

Seriously look at the numbers that were on page 1 of this column. Seriously we pulled the hose reels off our trucks because we feel anything less than 1 3/4 is useless. Also I feel the 2 1/2 is used a lot less than it should be because it seems like the municipal depts in the area jump right for the 1 3/4 even if it is big fire and there's not a lot of manuvering problems. There's no reason to not take in a 2 1/2 on a confirmed structure fire in a typical ranch house, get in and get it done.

[pumper41]

All fire services in Australia use 1.5 inch. Personally I've never had any problems with it, the manoverability is great and I can't complain about the flow rate, 95 to 125 gpm no problem. If we need more we go to 2.5 inch (Vollie Dept) or 2.75 inch (Career Dept).
My vollie dept look at 2 inch as an attack line about 5 years ago, everybody hated it, due to weight and difficult manoverabilty.

[Rescue101]

We've been using inch and three quarts and two inch for probably 15 years.You can have my 1.75 when you pry it from my cold dead fingers,there's no way I'd go back to 1.5.We use automatic nozzles,if you need some more firepower just crank up the juice.The difference in knockdown between the 1.5 we used to use and the 1.75 with the auto nozzle is quite dramatic.I'm not very big,240# in full gear and I have no problem bulling the 1.75 around.T.C.

[arhaney]

We recently changed to 1.75 attack hose. I love the increased knock down of the increased GPM's you can deliver! On the down side you do have a lot more reaction force to deal with at the higher nozzle settings. My advice.......if you can't handle it, just turn down the nozzle. The other down side for a rural department is your water supply, you can empty that 1,000 gallon booster tank in 5 or 6 minutes easy! But at the same time darken the fire so much quicker.