Off Road Vehicle Fire Prevention: 3 Important recommendations to the success

In general, the greatest fire hazards associated with mobile equipment are in the fuel pump, starter, exhaust ducts, turbochargers, torque converter, collection tray under engine or transmission and hydraulic pumps.

This article has the historical of mine equipment fire occurrences at Vale company in Brazil (Amazon rainforest) and recommendations for off road vehicle fire prevention.

Recommendations off road vehicle fire prevention

It is worth mentioning that any change in the original design of machines may affect off road vehicle fire prevention the following aspects:
• Operation of the equipment;
• Performance of systems;
• Safety of the equipment;
• Maintenance.

This instruction contains basic recommendations off road vehicle fire prevention on the various systems of the equipment, such information will provide important considerations to ensure:
• Security;
• Reliability;
• Efficiency of off road vehicles products;
• Efficiency of the off road vehicle fire suppression system.

Safety recommendations for off road vehicle maintenance:

• Before performing any repairs or maintenance, read and understand all safety information contained in the equipment manuals;
• Before starting activities on the equipment, know the operation of its systems and components;
• Read all “Safety” alerts on the machine prior to operation, lubrication or repair. Inappropriate actions on this product can be dangerous, resulting in injury
or death;
• Always use all personal protective equipment that is required by working conditions;
• Do not wear loose clothing or adornments that can get caught in moving parts of the machine;

• Use at least three support points when getting on or off the equipment. Keep your hands free of tools or materials;
• To avoid burns, be alert to hot parts and fluids, be careful when removing reservoir caps and vents on the machine to avoid being sprayed by pressurized
liquids;
• Do not smoke when inspecting the battery electrolyte level. Never disconnect any circuit from the charging unit or battery when operating. Avoid contact of
the battery electrolyte with your skin or eyes;
• Relieve all pressure on the systems before removing any lines, accessories or related items.
• Always make sure that all locking devices are applied correctly.

These items are crucial for the Off Road Vehicle Fire Prevention.

Off road vehicle fire suppression system

Equipment operating in mining, due to continuous use and severe working conditions, is permanently at risk of fire. Its motor and hydraulic parts are always heated and any leakage, be it fuel, lubricating oil, hydraulic oil, or even overheating of the grease in the bearings and joints can cause a fire principle, which, if not immediately extinguished, will expand to all equipment, putting the operator’s life at risk and causing total loss of equity / investment.

With the advancement of technology, equipment manufacturers are developing more and more powerful / productive machines every day and at the same time are reducing pollutant emissions. The disadvantage of these advances is the increase in heat throughout the engine compartment and hydraulic components, creating additional and more serious fire risks. In the event of a fire, the powder agent system can act and suppress the fire, but due to the high temperature and other factors in which the equipment presents itself, it may reignite.

Like equipment, fire fighting systems also evolve to meet needs more accurately. Manufacturers have adapted to use the liquid agent system as the second to be discharged, as it has a similar fire-extinguishing function, however, with the cooling capacity of all heating areas.

As the main manufacturers of fire suppression systems for mine equipment, we can highlight the companies Afex, Ansul and Kidde.

Therefore, adapt and standardize the location of accessories in the equipment cabin within the recommendations.

Do not mount fire suppression equipment in access places that prevent or restrictthe movement of people in the event of an emergency. This makes maintenance difficult and reduces the efficiency of the system. The equipment must provide easy access to all components of the machine.

Do not weld components of the fire suppression system of off road vehicles on removable plates of the equipment, in order to hamper maintenance activities and daily inspections.

These items are crucial for the Off Road Vehicle Fire Prevention.

Hose lines hydraulic

Study the installation of the off road vehicle fire suppression system at the entrance of Cables and Cables of the Cabin.

Paint with Metacaulk Cable Coating the arrival of Hydraulic Cables and Hoses in the control cabin. Caulk inlet tubes with Fire Sealant.

Install the off road vehicle fire suppression System at the Cab Cable Entry. Make closure with the system in two openings of the Box for Control cabin diameter 100 mm

The hoses and clamps of the systems must be inspected periodically in order to guarantee a safe and continuous operation of the system, therefore, inspect
and evaluate the replacement of any hoses that have the following conditions:

• Cracked, soft, dried, worn, cut hoses, exposed steel webs, bubbles, bent, crushed, signs of leakage at the crimp point;
Inspect and replace all clamps that meet the following conditions:
Cracks, laxity, and structural damage;

• The torque of the hose clamps must be constantly checked due to constant variations in pressure, temperature, expansion and contraction

Always use a board or piece of cardboard when you check for a leak. Fluid leaking under pressure can penetrate body tissue

See some examples and suggestions for correction below:

The fire suppression hose (1) is in contact with a hydraulic hose. This will cause damage (3) to the surrounding components (2).

The lubrication hose (4) is being used to support fire suppression hoses (5) in the frame. This increases the stress on the hose and creates points of friction between the parts.

Fire suppression hose (7) fixed to a hydraulic hose (6) by means of a plastic clamp (8). This places unacceptable stress on the hydraulic hose.

Fire suppression hose (10) in constant contact with the cutting edge of the equipment structure.

Do not tie the shield (6) around the hose (5) as protection against wear. Secure the hose in a fixed location using mounting brackets eliminating contact between hoses and other components.

Do not install fire suppression distribution blocks (7) in a location that allows contact with Caterpillar machine systems.

Use mounting brackets in the appropriate dimension to fix the hoses by removing the contact between the hose (11) and the edges.

Properly separate the hose at the mounting location (4). Use mounting brackets to remove all contact between the hoses at the mounting locations.

Correctly separate the contact between fire suppression components (8) and machine systems to avoid friction between the parts.

These items are crucial for the Off Road Vehicle Fire Prevention.

Below are other instructions related to hydraulic lines:

• In order to map all the items mentioned, it is relevant to evaluate and carry out employee training for correction, inspection and maintenance in general in hoses;
• It is essential that the correct application of hoses is analyzed in the manual, evaluating the specification of the
system material and pressure that the hydraulic line requires as recommended;
• Perform the complement as recommended by the manufacturer in all hydraulic compartments;
• Do not change the design / size of the hoses;
• Do not perform welding or reuse of hose terminals;
• According to the mapping of critical and most used hoses, evaluate the application of protection thermal and spiral protection.

These items are crucial for the Off Road Vehicle Fire Prevention.

Installation and torque procedure for hydraulic hose flanges:

• The tightening sequence of the flanges that hold tubes and hoses to the machine is critical for the machine to function properly;
• The sealing surfaces of tubes or hoses must be firmly attached to the maintenance component (control valve, cylinder, hydraulic motor, etc.);
• Perform this procedure before the final tightening of any flanges that are used to secure pipes to the machine. Use the standard torque specification
table for the correct tightening of the screws;
• Do not improvise “similar” seals in high pressure hydraulic systems. There may be discrepancies in terms of working pressure, temperature, fluid and
manufacturing material.

(1) Seal face connection with ring (1A) Ring housing
(2) seal ring
(3) nut for the sealing face of the ring

NOTE: Use only 50% of the torque value when the connection or nu is made of non-ferrous material

Do not improvise rings and similar seals, your technical specifications will be different, use as recommended by the manufacturer in the manual:

Example: O-rings 6V-9746 and 228-7092, have the same dimensions, but have different colors, material and specifications:

• The 6V-9746 ring is brown in color, the manufacturing material is NBR (standard nitrile compound). The ring 228-7092 has a blue

• color, the manufacturing material is FKM (fluorocarbon compound).

Despite having the same dimensions, greater heat resistance is one of the differentials of the FKM seal compared to the NBR seal. In contrast, the wear resistance of FKM is slightly lower than that of NBR, according to the Parker compound table.

These items are crucial for the Off Road Vehicle Fire Prevention.

Details of the differences shown in the previous slide:

Text in portuguese

Electrical System

Special care is needed with wiring or electrical harnesses, as it is a very vulnerable in conditions where he can be stepped on, hit by rocks or machine debris and can rub against other components.

Avoid creating situations that could damage the electrical system, as it can generate the following conditions:

• Short circuit;
• Loss of machine control;
• High machine downtime for maintenance
• Complex diagnostics.

The following slides show some abnormalities and also suggestions to minimize electrical problems.

Faults Found in Electrical Harnesses:

For example, some abnormalities are found in electrical harnesses regarding their application and routing through equipment, loose connectors,
inappropriate terminals and harness interference on sharp edges:

Do not use a hose as a mounting location (2) for an electrical wire harness. Vibration, excessive load and movement of the hose can damage the harness.

Do not allow interference between the hose lines and the equipment’s electrical system. The machine harness (4) was damaged by the fire suppression hose (3).

Perform the correct strain relief technique (2) of the electrical wires, which is necessary to ensure that the movement of a wire does not cause it to break in the sensor housing (3).

Make the correct routing of wires and harnesses through metal plates. Use an eye ring (8) when the electrical wires are routed through sheet metal surfaces to eliminate contact with sharp edges.

Use support brackets (6) or mounting brackets of the appropriate size (7) to protect and secure electrical wires and harnesses.

Do not weld (1) the hose clamp fixing toggles near welding joints of structural elements. Welding too close to a structural weld can create a stress lift that will propagate cracks in the structural element.

Make sure that all connectors have the seals and that they are clean and free of moisture before coupling them. Try to separate the connectors to make sure they are locked together

Clamps and lashings must not be less than 150 mm from a connector to introduce moisture and tension the wires.

Connectors that are not being used must be sealed. Use the corresponding connector and close all holes with sealing plugs to prevent moisture from entering.

Use the correct eye terminal according to the diameter of the screw. When they are too big they can come loose or break.

Flat washers must be placed between the screw head or nut and the eyelet end of the wire or cable to allow tightening without causing the wire or cable to rotate around the screw or case. Star washers must be mounted between the terminal and the component

Do not attach a whip, cable or wire in such a way as to create unnecessary tension and tend to pull and damage the wires.

Do not leave fire suppression hoses loose. The hose (1) is not attached and is in contact with the battery cable. This can damage the surrounding components.

Route the harness so that the wires are straight when entering the connector so as not to get moisture. Secure the connectors to the fixing clips to prevent vibration and bad contact with them. Never use a screwdriver or pliers to disconnect connectors, this can cause damage to the product and to yourself.

Use clad clamps for cables with larger diameters to support them properly. Smaller diameter wires can be attached to individual clamps with plastic clamps.

Currently we find some abnormalities in the wiring harnesses regarding the repair method, insulation, etc. Such situations are very conducive to starting a
short circuit and subsequent damage to the equipment, below are some examples of incorrect repairs:

The following is the correct repair procedure for harnesses.

These items are crucial for the Off Road Vehicle Fire Prevention.

Recommendation 1 for Wiring Harness Repairs:

STEP 1: Identify the damaged area of the harness and identify the root cause of the damage. Before implementing harness repair, consider how to reposition or protects you from recurrence of failure.

STEP 2: Remove the wire protection mesh using tool 377-6198 and expose the wires in the damaged area until they are long enough to be repaired without undue tension after the repair is complete.

STEP 3: Isolate all damaged or broken wires to be repaired and clean them properly to prepare for repair with sealed splices.

STEP 4: Remove the damaged section of each wire, cutting just enough to a point where all the wires are intact. Check that there are no more notches or damage to the other harness wires.

STEP 5: Strip between 6.4 to 7 mm (N) of wire insulation, but be careful not to cut or cut copper wires. Inspect through the inspection hole (M). The insulation will be within 1.5 mm from the rear of the terminal when the wire is properly inserted.

STEP 6: Insert the terminal next to the wire in the 1U-5804 crimping tool. Make sure that it is properly adjusted to the size of the wire and terminal being pressed.

STEP 7: Inspect the terminal to make sure that all wire cables are pressed. Check that the crimp point is in the center of the area of the terminal.

STEP 8: After all terminals have been twisted, use electrical tape to perfectly cover only the ends of the worn mesh.

STEP 9: Attach pin and socket to the “Jiffy” splice. Select the same one according to the desired application and wire size.

STEP 10: Perform a slight tug on the wires to confirm that the pin and socket are correctly engaged. Run The electrical / functional check on the circuit to ensure that the repair was effective before isolating the repaired harness.

STEP 11 : Use electrical tape to cover perfectly the ends of any frayed braid and ensure that all seams are secure in place

STEP 12: Secure the ends of the repaired site with clamps using the 4C-5877 tool.

These items are crucial for the Off Road Vehicle Fire Prevention.

Recommendation 2 for Wiring Harness Repairs:

STEP 1: Identify the damaged area of the harness and identify the root cause of the damage. Before implementing harness repair, consider how to reposition or protect it from recurrence of fail.

STEP 2: Strip between 6.4 to 7 mm (N) of wire insulation, but be careful not to cut or cut copper wires. Select the correct “Butt” splice to be used according to the wire gauge.

STEP 3: Use the 9S-9150 terminal crimping pliers to press the stripped wire to the specified point of the terminal in use.

STEP 4: Perform a light tug on the wires to confirm that the splice is properly secured. Perform an electrical / functional check on the circuit to ensure that the repair was effective.

STEP 5: Use the 9U-6070 heat blower tool to shrink the seam insulation. Visually confirm that there are no openings and that the adhesive is properly sealing the wire insulation.

STEP 6: Use electrical tape and plastic clamps to ensure that all worn seams and stitches are properly secured in place.

These items are crucial for the Off Road Vehicle Fire Prevention.

List of parts and tools for wiring harness repairs

Battery Compartment

Analyzing the battery compartment, some abnormalities can be highlighted, such as lack of locking device (fixation), cables and electrical harnesses in constant friction, tensioned cables, damaged terminals, etc., here are some examples:

Some relatively simple steps are suggested to ensure greater reliability and longer battery life:

•Do not allow the battery cable ends to come into contact with each other or with the machine. Improper starting procedures can cause an explosion. Resulting in personal injury. Always connect the positive cable (+) to the positive battery pole (+) and the negative cable (-) to the negative battery
pole (-).

•Dubbing only with a power source with the same voltage as the machine to be dubbed. Turn off all lights and accessories on the paralyzed machine. Otherwise, they will work when the power source is connected.

•Check the electrolyte levels at appropriate intervals. Standard or conventional batteries should be checked every 100 hours. Electrolyte levels should be checked in low maintenance batteries every 250 hours. No acid level checks are required or can be performed on maintenance-free batteries.

• Avoid sparks and do not smoke near the batteries, their vapors can cause explosions and serious injuries.

It is relevant to check the following conditions when inspecting the batteries:

• Is there any indication of damage or corrosion to the battery terminals, the battery case or the wiring? Clean or replace the necessary components

• Are the terminal and bracket grips correct? Vibration is a major cause of damage to batteries. Bad contact generates low system efficiency and damages
the battery poles and terminals.

• Is there debris under the battery? This must be removed, as this can cause holes and result in loss of electrolyte. Are all ventilation covers correctly in place? The loss of ventilation covers can pose a potential hazard and allow contamination of the battery.

•Are the alternator belts tight? If not, the battery will not charge properly and poor performance will result.

•What is the alternator output voltage? Use a voltmeter to check. This will identify both low and high charge voltages that can damage a battery. The alternator charge voltage must be 13.5 to 14.5 volts for a 12-volt system and 27.0 to 29.0 for a 24-volt system.

•While maintenance-free batteries do not require electrolyte checks, perform the previous steps every 1,000 hours to obtain maximum battery life.

These items are crucial for the Off Road Vehicle Fire Prevention.

Study the application of fire-resistant paint on battery cables

Carry out the cleaning and painting of the cables with Metacaulk Cable Coating, extending the battery until starting and starting until the control cabin. Approximate length of 10.00 meters and perimeter of 200 mm.

Other recommendations for this item:

• Evaluate the route and locations of the battery powered cables;
• Evaluate the protection of the circuit powered directly by the battery and with a higher load
• Assess battery cable attachment
• Assess the quality of the applied battery
• Perform battery dubbing as recommended by the manufacturer
• It will be necessary to evaluate together with CAT improvements related to circuit protection and also to evaluate the feasibility of including in the logic of the Shutdown system, the de-delegation of the battery and the starter.

The electrical part related to the starter and alternator are also relevant to maintain the integrity of the equipment, below a small example of incorrect items
and then objective recommendations to maintain the full functioning of the components:

Non-standard starter grounding cable (in red), which creates a risk of short during or after maintenance. Terminals of the starter motor power cables without the insulation caps, which creates the risk of short due to contact against other parts of the equipment.

Terminals of the alternator power cables without the insulation covers, which creates the risk of short due to contact against other parts of the equipment.

Recommendations for better reliability of these components:

•Cable dimensioning.
•Component positioning.
•Check the correct torque of the terminals and their insulation.
• Eliminate any interference from the power cables with the equipment chassis.

These items are crucial for the Off Road Vehicle Fire Prevention.

Recommendations for evaluating the application of the starter motor cable de-delegation system, below view of the starter power cables

Electric Control:

When the start switch is turned on, the control bleed will keep the auxiliary start relay energized for 70 seconds; and for 70 seconds the power cables of the
starters will be energized, thus avoiding the closing and opening of the relay contacts with load.

Cover adaptation:

New manufactured access cover Opening on the platform.

Opening on the platform

Electric Control:

Window next to the battery box to install the relays.

The cover was replaced and screwed to facilitate maintenance, thus leaving the structure unchanged.

Relay coil power harness output of the starters.

Auxiliary relay location, which supplies the relays of departure.

These items are crucial for the Off Road Vehicle Fire Prevention.

We suggest to implement a thermographic analysis of the electrical starting circuit and all electrical connectors of the equipment in the preventive of 2,000 hours in order to identify bad contact of pins / sockets that can generate a temperature increase by short circuit. Following are examples:

Batteries

Cabin connectors

Proper welding procedures are necessary to prevent damage to electronic controls and bearings. The following steps must be followed:

Stop the engine (1). Set the engine start switch (3) to the OFF position;
Stop the engine (1). Set the engine start switch (3) to the OFF position;
Set the main switch (4) to the OFF position. If there is no main switch, remove the negative cable (5) from the battery (6);
Disconnect the J1 / P1 and J2 / P2 connectors from the ECM harness;
Attach the ground cable (11) from the welding machine to the component (9) to be welded. Place the clamp as close as possible to the weld (2) and
make sure that the electrical path (10) from the earth cable to the component does not pass through any bearings or electronic components (7);
Protect any wiring or harness (8) from heat and welding spatter; Use the appropriate standard;
welding procedure;
Disconnect the connectors from the ECM.

When cleaning / washing trucks, it is worth paying attention to the following factors:

Avoid directing high pressure water jets at connectors and other electrical parts.

Observe and avoid the direction of water jets in the seal of the rear cover of the cabin.

These items are crucial for the Off Road Vehicle Fire Prevention.

Off road vehicles fire history

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Fire Protection Safety Intelligence

Off Road Vehicle Fire Prevention: 3 Important recommendations to the success

Table of Contents

Recommendations off road vehicle fire prevention

Safety recommendations for off road vehicle maintenance:

Off road vehicle fire suppression system

Hose lines hydraulic

See some examples and suggestions for correction below:

Below are other instructions related to hydraulic lines:

Installation and torque procedure for hydraulic hose flanges:

Details of the differences shown in the previous slide: