Park brake test...

[FIREMECH1]

I'm curious to know what you guys do for your "daily" park brake test.
Do you have an SOP/SOG that defines how you do it???
Put in gear and if it holds, it's good??? Or do you have a set rpm increase above idle that you use?? Or, a set rpm that you go up to, to see if it holds???

Here's my problem. The FD engineer took 3 rigs OOS because the park brake wouldn't hold when throttled up to 1,200 rpm's in gear. I was called out to find and correct the problem.

The FD SOP/SOG is to put it in gear, note the idle rpm, and gradually increase the throttle 200-300 rpm's over idle. If it stays, your good. If it moves, call the shop.

After a careful inspection and test of the park brakes, all 3 were returned into service without any need of adjustment. And FYI, I am extremely cautious when it comes to brakes on these rigs.

FM1

[Johngagemn]

I always just checked them in gear at idle, never tried to throttle up. Shoot, if you throttle up enough in gear you can overcome the brakes, climb a wheel chock, and go pick up a hamburger at McDonald's, and I've witnessed probies trying to do all three!

[MColley]

Our department policy is to park the truck on a slight incline facing down the incline apply the park break and throttle up 200 or 300 rpm above idle. That “above idle” is important because at one point it was written to take the truck up to a set rpm but we were finding a lot of trucks failing because the idled low and any more than that 200 or 300 rpm increase was causing the truck to move. In saying that typically if the truck moves they just put a little bit of a turn on the breaks even thought they might still be in adjustment just to stop the rig from moving.

[FIREMECH1]

Our department policy is to park the truck on a slight incline facing down the incline apply the park break and throttle up 200 or 300 rpm above idle.

Our FD's SOP/SOG for going 200-300 rpm's over idle on level ground, is to substitute the parking on an incline. Either facing downward or upward.

I'm astonished, yet surprised at the none responses from others.

NOTED.

FM1

[txgp17]

I don't think throttling up a certain number of RPM's to check is the right way to do it.

One truck may have a 450 HP engine and 6.14:1 ring & pinion gears. A truck like that would climb trees as long as it had traction. While another truck may have a 325 HP engine and 4.88's.

I can tell you what the NFPA manufacturer's test is, which you likely already know. The parking brake is supposed to bring the fully laden vehicle to a complete stop from a speed of 5 mph within 20’.

[BoxAlarm187]

I'm astonished, yet surprised at the none responses from others.

NOTED.

We don't do a dedicated brake test at our department. In fact, I feel somewhat ashamed that in my many years of doing this for a lot of different departments, that I've never heard of anyone doing a brake test.

[FIREMECH1]

We don't do a dedicated brake test at our department. In fact, I feel somewhat ashamed that in my many years of doing this for a lot of different departments, that I've never heard of anyone doing a brake test.

Seems like you're not the only one that doesn't do it, or has never heard of it. I thought it was something every department did. (???)
Maybe it's something our FD decided to do, to make sure the spring brakes will hold on the hills. Not sure why it's in their SOP/SOG, but it is.

FM1

[rm1524]

Seems like you're not the only one that doesn't do it, or has never heard of it. I thought it was something every department did. (???)
Maybe it's something our FD decided to do, to make sure the spring brakes will hold on the hills. Not sure why it's in their SOP/SOG, but it is.

FM1

I have heard of it, but we don't do it or have a policy for it. It is not a bad idea.

[kuh shise]

Some CDL parking brake (spring brake) tests reference rolling at low speed and setting the spring brake. This test specifies a minimum braking rate of 12% of gravity. Since "G" is 32 ft/sec*sec. This is 3.84 ft/ sec * sec. Rolling at 5 mph is 7.33 ft/ sec so stopping should be accomplished in 1.909 seconds. Assuming a uniform decileration rate, the rolling distance after the brake starts dragging will be (7.33 / 2) * 1.909 = 6.996 ft. But you must only start measuring after the brake starts to apply, not when you pop the yellow button. Another way to test would be to stop on a 12% grade, set the spring brake, and see if the truck stays still.

[FIREMECH1]

I don't think throttling up a certain number of RPM's to check is the right way to do it.

One truck may have a 450 HP engine and 6.14:1 ring & pinion gears. A truck like that would climb trees as long as it had traction. While another truck may have a 325 HP engine and 4.88's.

I can tell you what the NFPA manufacturer's test is, which you likely already know. The parking brake is supposed to bring the fully laden vehicle to a complete stop from a speed of 5 mph within 20’.

Yep, I know what the NFPA standard is set to. But that 20' is too long in my opinion. If push comes to shove with those that think they know, I do a 5mph test. If it doesn't stop in 3 seconds from popping the valve, then we MAY have a problem.

As for HP and rear gearing, that issue is really not an issue. I've got a rescue/hazmat 500HP with 5:37 gearing on a single axle, and does OUR park brake test just fine.

FM1

[txgp17]

As for HP and rear gearing, that issue is really not an issue. I've got a rescue/hazmat 500HP with 5:37 gearing on a single axle, and does OUR park brake test just fine.
FM1

Yes,
A parking brake that can resist your test with the 500/5.37 combo is a good example of a good parking brake.

However, a 350/4.88 combo would exert much less torque on the wheels. So a weaker parking brake on that truck MIGHT pass that test, but not hold adequately on a steep grade. Emphasis on MIGHT.

[EngineCO38]

When I do my weekly pre-trip of the trucks (The pre-trip that is defined in the Vermont DOT CDL manual) I rev the engine to 1,000 RPM's, and if it holds it passes its inspection. If it moves, well I recommend it taken out of service.

That's how I do it with all the big vehicles I drive, our rigs at the station, my 02' International box truck at Budweiser. And whichever school bus I happen to be driving on the weekends.

[LFD2203]

We don't do a dedicated brake test at our department. In fact, I feel somewhat ashamed that in my many years of doing this for a lot of different departments, that I've never heard of anyone doing a brake test.

Remember, disaster begats code. Those departments with a parking brake testing policy, procedure, guide, etc. are probably those who have had an apparatus roll away with the brake set. Just sayin'

[ChiefKN]

Remember, disaster begats code. Those departments with a parking brake testing policy, procedure, guide, etc. are probably those who have had an apparatus roll away with the brake set. Just sayin'

My wife's car was crushed (it was parked) by a 3000 gal FD tender that rolled out of the auto body shop.

Of course, the parking brake wasn't set. A critical step in the process.

[FIREMECH1]

Remember, disaster begats code. Those departments with a parking brake testing policy, procedure, guide, etc. are probably those who have had an apparatus roll away with the brake set. Just sayin'

Nope, not here. It is something called being "PRO-ACTIVE", than being RE-ACTIVE. Some should study the difference. 'Just sayin'

FM1

[RhodellVFDmike]

As a professional school bus operator and engineer for our fire department, the proper way defined in WV is having the park brake set (assuming you are using air brakes) put unit in drive, gently acelerate the engine to 1200 RPMs. If the vehicle moves any, then the brakes needs serviced. You should also remember to check for air leaks. You should build your air pressure to 100 lbs, and turn engine off, listen and watch gauge for 1 minute. Then hold service brake for 1 minute and listen and watch gauge. A drop in pressure more than 3 psi indicates a problem. Your compressor should build from 85 lbs to 100 lbs in 1 minute or less. If it doesnt, there is another problem. The brakes are in size to acomidate the respective vehicle they are on. Whether it is a 10 ton vehicle with a 220 hp engine or a 30 ton vehicle with a 410 hp engine, Its all the same.

[Nullygarhoe]

Per the "Fire Service Pump Operator: Principles and Practice" pg. 139 Parking Brake Test "Make sure that the fire apparatus is in a safe position and has plenty of room to perform this simple brake test. With the fire apparatus turned on, allow it to move forward at a speed less than 5 mi/h (8km/h). Apply the parking brake. If the fire apparatus does not stop, bring it to a halt using the service brakes and have the apparatus inspected by a qualified mechanic."

If something does happen and it goes to court, you as the engineer and your department, have a legal leg to stand on. This test is in a text approved by NFPA and IAFC. By going out and "making up" your own tests potentially puts you and your department in a position of liability.

If you and your department are going to create SOG/SOP's then refer back to the textbooks you used in school.

"It sounded like a good idea..." and "I thought it was a good idea..." doesn't hold a whole lot of water in court.

[FIREMECH1]

Per the "Fire Service Pump Operator: Principles and Practice" pg. 139 Parking Brake Test "Make sure that the fire apparatus is in a safe position and has plenty of room to perform this simple brake test. With the fire apparatus turned on, allow it to move forward at a speed less than 5 mi/h (8km/h). Apply the parking brake. If the fire apparatus does not stop, bring it to a halt using the service brakes and have the apparatus inspected by a qualified mechanic."

How many feet, or how many seconds do I let it roll before it stops????

Simple question.

FM1

[LVFD301]

When it takes out the doors or the wall - you let it roll too far.

[CaptOldTimer]

We have done this before but at a speed of 25 mph, near the training school and also at the shops, and apply the park, aka maxi, brake. In 100% of these tests the rig stopped.

Not sure the distance it took.

Maybe in quarters the members may test it daily but not an usual case. No in writing to do so. Just at a drivers whim.