ASK ERNIE Summer 2012


The Apparatus Maintenance Expert

CarolinaFireJournal -

08/01/2012 -

What is the correct pump testing procedure for my annual pump test?

Test procedures can be found in chapter 18 of the “NFPA 1911, 2012 Edition.” This includes conditions of the test site, environmental conditions, and equipment required to perform the test. If it is impractical to perform the test at a standard test pit or water source, alternative methods may be used as authorized by the AHJ (Authority Having Jurisdiction) (NFPA 1911, 18.6.2).

As an example, new style portable above ground test pit services can be used to test the pump. If this procedure is utilized, it is recommended that it be repetitively used each year so that equal comparisons may be made to determine continued pump conditions. If testing at a pit or open water source, the drafting lift shall not exceed 10 feet or be less than three feet. Primary tests consist of:

  • A primer/vacuum test
  • Pressure control device test
  • 100 percent test of rated flow at 150 PSI for 20 minutes
  • A spurt/overload test at 100 percent of rated capacity at 165 PSI for five minutes; 70 percent test of rated flow at 200 PSI for 10 minutes; 50 percent test of rated flow at 250 PSI for 10 minutes.

This test shall also be performed whenever major pump repairs have been performed, or any other condition that may affect pump output (engine or transmission overhauls are examples). If the testing procedure indicates a failure of any portion of the test, the testing stops and any needed repairs are then performed by trained personnel. The test procedure should be performed in a complete process from beginning to end without interruption.

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What air conditioning maintenance needs to be done?

Routine and annual inspection of all components of the A/C system are a necessity. Inspect the condenser for debris in the fins and clean as needed. Perform a pressure and full function test of the system — recording high side and low side readings and the output temperature in the cooling plenum and outlets. The EPA mandates that A/C service and inspections may only be performed by licensed HVAC technicians. Rely on the manufacturer’s specifications and test procedures.

What should annual services and inspections on my truck include?

To perform to the recognized industry standards, you must first perform a Federal Annual Safety Inspection of the apparatus. You should have in your possession the factory operations and service manual and a copy of NFPA 1911, 2012 Edition Out-of-Service and Maintenance guidelines as a tutorial. If your agency does not have a copy of NFPA 1911, refer to the Uniform North American Out-of-Service criteria and common best practices for the maintenance of commercial vehicles.

Any defects found during the recommended inspection must be performed at that time. Only certified Emergency Vehicle Technicians or trained maintenance personnel as authorized by the AHJ may perform maintenance and repairs of the emergency services vehicles. Each and every agency should have a check off form for each of the annual test procedures. NFPA and IFSTA have excellent typical forms that your agency can use as a template to formulate your own set of inspection forms. You can find these sample forms at the back of the IFSTA Pumper Apparatus Driver/Operator Handbook, the Aerial Apparatus Driver/Operator handbook and NFPA 1911.

Should I request to be present for my acceptance test when picking up my new truck? What are some things to look for?

You (a fire service expert) and a mechanic representing your agency should be in attendance. If you as a fire service expert are also up on all mechanical issues, you need only you in attendance. More eyes and fingerprints on the acceptance testing the better.

Each agency formulates a list of items that it believes to be important to assure the longevity of the apparatus in their service. The acceptance test is performed by the receiving agency at time of delivery to confirm compliance with all items listed in the apparatus specifications document. A thorough inspection should include a line-by-line review of each item listed in specification document, followed by a performance test of the pump — regardless or whether or not it was performed at the factory — and a full road test to assure that it meets the needs of the agency and performs without overheating or activation of warning alarms or devices. A reference of items to consider are listed in NFPA 1911, 2012 Edition; Section 4.18

Since the emission changes, what different engines are available for custom firetrucks?

For custom build apparatus chassis, Cummins (not Cummings) is the leader and some argue that Cummins is the most pro-active as it pertains to custom design of fire apparatus software and emissions issues. Other leaders include Detroit Diesel, Navistar International and Mercedes Benz. Commercial truck manufacturers all have motors installed in their chassis that can be registered for specific fire service application. Fire apparatus motor warranties provide extended length in time, usually to standard five year warranties with extended warranties up to 10 years at an additional cost.

With the complexities of emissions systems and electronics I recommend that all purchasers take the extended warranties. Roll the cost of extended warranty into the bid pricing when puting your specifications together. I also recommend that you include a specification for a laptop diagnostic computer. This should include all appropriate diagnostic software with prepaid licensing in your specification so that motor and other diagnostic tasks, hardware and software costs are embedded into the cost of the apparatus. This may add an additional $5000-$7000 to the $350,000 - $850,000 pumper or up to $1.3M for an aerial. Any licensing of software should be borne by the apparatus builder/final stage builder.

My fire truck seems to overheat frequently. What are some things I can do?

Ya got ol’ Uncle Ern’ scratching his head on this one. Is the truck new? Has it overheated since delivery? Have personnel created the issue? What type of apparatus is it? Is the overheat a new issue? Did it come on suddenly or all at once? Does it occur only under load while climbing substantial grades? Does it occur only at ambient temps above 90 degrees Fahrenheit?

If it has overheated since new, I have to deduce that the cooling system is not up to emergency services tasks. Has the final stage builder built in issues during the build process?

Let’s discuss apparatus type. If your old apparatus was one that required the opening of the hood or engine enclosure to remove heat during operations, there could be an issue with the new apparatus. If the new apparatus is a tilt cab and your operators are tilting the cab to move heat out of the engine area during pumping or parked operations, it will cause an overheat. There MUST be a barrier between the cool air side and the hot air side of the radiator. If the cab is tilted, the hot air recirculates to the cool air side and can quickly cause an overheat situation. If the heat barrier between the cool air side and hot air side is deteriorated, correct the barrier materials. Keep the tilt cab lowered.

If the issue came on over a long period of time, I have to question the condition of the cooling system. Are you sending coolant samples to a spectrochemical analysis during the annual service? Has someone installed the wrong type of coolant as a replenish procedure. Cross contamination of coolants may (most likely will) cause an issue of overheat and complete contamination of the cooling system.

Is the radiator plugged with corrosion at the tube openings at either end? If so, get it repaired or replaced. If the issue came on suddenly, look for debris in the fins area and take corrective action. You may find that the radiator opening has other coolers upstream from cooling air flow. You may have an air-to-air charge air cooler and air conditioner condenser installed in front of the coolant radiator. Make absolutely sure that there is nothing between the sandwiched coolers that will impede air flow through the coolers/radiator. (This is the most common issue in overheat, followed by cooling system issues).

Should pump packing be replaced on a time line or just when it leaks?

Simple pump shaft packing leaks do not require replacement of the packing, only a routine re-adjustment by properly trained EVT or station personnel. Local agency routine maintenance may include a time line for replacement of leak sealing packing materials. Normally, when routine adjustments can no longer stop a leak, the packing will be replaced. I find that when untrained personnel overtighten the packing, it will cause pump shaft damage that is not reversible or correctable. If the shaft is damaged, replacement of the packing will correct a leak for a short time and will require that you continually re-tighten the packing but will finally result in adjustments that no longer stop the leak. The end result is the disassembly of the pump and an overhaul to install a replacement pump shaft. The repair facility will normally order a replacement, exchange replacement pump shaft/impellor assembly to save time and money. Another situation that requires a packing replacement is when the soft packing material becomes so hardened or becomes stuck to the stuffing box bore.

What is a good rule to use when backflushing my pump?

There are many rules of thumb that you can use to judge when a flush is appropriate. Does your local agency have a prescribed procedure and time line? Is the pump/tank water brown/black/orange? This can indicate the presence of iron oxides in the water — generally a transfer of pump, plumbing or steel tank erosion through the electrolysis process. As the water becomes more concentrated with oxides it affectively becomes an electrolyte when water is circulating and can create an electrical charge, exacerbating the electrolysis issue.

To minimize internal pump and pumping system component degradation due to electrolysis, clean water should be retained in the on-board water supply. Part of the process is flushing and/or back flushing the pump. Apparatus that respond to routine and regular calls where water is routinely and regularly changed/refilled, a secondary replacement of the water is not needed. Regardless, your agency should have a backflush procedure to correct issues of debris lodged within the pump or inlet screens. To flush the pump, refer to the operators manual. If there is no procedure described, I suggest you perform the following procedure annually, or if you think there is an issue with debris lodged in the pump impellors.

With the pump engine shut down, drain the pump and remove all external caps/valves. Pick a single main manifold discharge, either right or left side. Connect a 2.5” hose from the discharge, open the discharge valve and connect a hose from your pumper to a second pumper connected to a hydrant. Open the hydrant and open a discharge from the active pumper to the one being flushed. Activate the second pump and increase the flow and water will flow through the pump being flushed from the discharge side to the open inlets.

If it is a two stage pump, operate the change-over valve several times to remove any captive debris from the internals of the pump. If you still suspect debris is captured in the impellor(s), send the pumper to the repair facility for visual inspection. The repair facility can use a bore-scope to inspect the pump internals and take any appropriate corrective actions indicated. Do not stand near any pressured hoses or near any outflow of water. Only personnel essential to the operation should be near either apparatus. If a second pumper is not available for the flushing procedure, locate a high static pressure hydrant (80-100 PSI if possible), to perform the flushing procedure.

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