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]

Sop

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