ASK ERNIE


”The Apparatus Maintenance Expert”

CarolinaFireJournal - Anthony D. (Tony) Bulygo
Anthony D. (Tony) Bulygo
08/07/2015 -

Are there any new NFPA 1901 changes that are being discussed? 

The answer is to go to the NFPA site, and go to the section that addresses the input from the general population.

What is the recommended service interval for your onboard hydraulic PTO generators?

As with any systems that vary from manufacturer to manufacturer, only the manufacturer can answer that question. 

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In a very generic way, NFPA 1911 indicates that all components of a fire apparatus must be serviced to manufacturer’s specifications and may not go beyond one calendar year.

Are there any suggestions for properly maintaining our on board foam system? 

As with any systems that vary from manufacturer to manufacturer, only the manufacturer can answer the question.  I will consider that you are asking about both foam proportioning systems as well as the compressed air foam systems (CAFS).  Performance testing for on-board foam proportioning system is covered in NFPA 1911, Chapter 20, inclusive.  Performance testing for the on-board CAFS is covered in NFPA 1911, Chapter 21, inclusive.

What NFPA chapters are involved in apparatus maintenance and building of apparatus?

Apparatus maintenance is covered, chapter and verse with the manufacturer’s maintenance manuals and is specifically spelled out in NFPA 1911, inclusive.  The specifications to properly build a fire apparatus are covered in NFPA 1901, inclusive; the Federal Motor Vehicle Safety Standards (FMVSS) manual; OSHA or individual state and local safety laws, regulations, and standards; the Federal Motor Carrier Safety Regulations manual, and NFPA 1911.

My fire pump has a severe air leak at the pump shift area what causes this? 

The causes are varied and numerous.  One has to view this as a situation of pump shaft condition, sealing type — mechanical or packing/stuffing style — age of the pump, etc.  If it is of the rope packing style, the old packing must be removed. This can be a difficult process.  Your uncle Ernie likes to remove the gland and then back-pressurize the pump.  Make sure all air is removed from the pump by bleeding the air and filling the pump with water prior to making the attempt to blow the packing by back-pressurizing from another pumper.  I have had to get the pressure up as high as 250 psi before the packing exits the stuffing box.  Be VERY careful.  After the removal of the packing, inspect the stuffing box and shaft.  If someone has over-tightened the packing and scored the shaft, no amount of re-packing will stop the air leak for the long term.  If the stuffing box uses the plastalic pellets as a seal material instead of the rope style, blow the old packing out and inspect the shaft for the same over-tightening damage to the shaft.  Shaft damage, depending on the severity, will require a shaft replacement.  If you have the mechanical seal type and it is leaking, the seal is destroyed and must be replaced. Procedures for replacement of the mechanical seal vary from manufacturer to manufacturer.  Follow their instructions.

Is there anything I can use to clean up the tread plate on our rigs? 

The shine of the aluminum diamonette is manufactured into the product.  Once the shine is damaged, it can be buffed to a new shine, but will never retain that shine.  Some products for shine recovery are better than others. 

What are the lighting requirements for warning lights on all fire apparatus or emergency equipment?

The lighting requirement for warning lights is covered very extensively in NFPA 1901, 13.8.11; 13.3.3(5); 13.4.7; 13.8; A13.8; 13.8.1 to 13.8.16 and NFPA 1911, 4.6; 8.12; and 7.1 and others.

What exactly is a Telma retarder?

The answer is too lengthy to cover it fully here.  However, you can view the description on the Telma site at: http://telmausa.com/products/operating-principle.  The simplistic answer is that there are two rotating iron masses likened to brake rotors that are attached to the driveshaft.  Between the two rotors are electromagnets that when charged with current, try to stop the rotating mass from rotating.  There is no contact between the rotors and the electromagnets.  The attempt by the magnets to stop the rotors generates substantial amounts of heat and slows the vehicle drive axle wheels at a rate consistent with the amount of electricity directed to the pole shoes. The biggest negative issue is the shock load that the system creates on the chassis’ electrical system.  The larger land based chassis can take over 600 amps of 12VDC power.

Your old answer man; Ernie.

(Disclaimer:  Uncle Ernie does not sell any product and is simply the purveyor of available information.)

— Ernie questions answered by
Anthony D. (Tony) Bulygo.

“Ask Ernie”
The Expert

 

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Issue 33.3 | Winter 2018

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