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newSchoolWorks.com › VoTechWorks › Transportation › Diesel & Heavy Truck › Preventive Maintenance for Diesel & Heavy Trucks › Lesson 2
TRN-DIES20-06 · Lesson 2 · 14 clock hours · demo

Shop Safety for PM: PPE, Lockout/Tagout, and Chemical Handling

Objective. Students will demonstrate correct donning of PPE required for PM tasks, apply a lockout/tagout procedure on a parked truck before beginning under-vehicle work, and safely handle and dispose of used oils, coolants, and aerosol chemicals according to OSHA Hazard Communication (HazCom) standards.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a certified examiner or master technician in the trade or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

VoTechWorks program approval and accreditation are still in progress. Credentials are issued only by the certifying bodies named in each program, after their own exams.

Why Shop Safety Matters in Preventive Maintenance

Preventive maintenance (PM) keeps heavy trucks on the road and out of the repair bay. But the same routine tasks — draining hot oil, opening a pressurized cooling system, sliding under a 30-ton vehicle — create serious hazards every day. OSHA data consistently shows that slips, chemical burns, and struck-by incidents rank among the most common injuries in truck shops. Understanding and applying the right controls before you touch a tool is not optional; it is the foundation of every PM job.

Personal Protective Equipment (PPE) for PM Tasks

PPE is your last line of defense after engineering and administrative controls have already reduced the hazard. Selecting the wrong PPE is nearly as dangerous as wearing none at all.

Eye and face protection. Safety glasses with side shields meet ANSI Z87.1 and are the minimum for general shop work. Chemical-splash goggles are required any time you open a cooling system or work with brake cleaner and other aerosol solvents, because liquid can travel in any direction. A face shield adds a second layer and is recommended when there is splash risk above the eye line — for example, removing a radiator cap on a warm system or pressure-testing coolant circuits.

Hand protection. Nitrile gloves (minimum 4 mil thickness for general PM, heavier gauge for extended chemical contact) resist engine oil, coolant, and most petroleum-based solvents. Latex allergies are common; nitrile is the standard shop choice. Never use cotton or leather work gloves when handling chemicals — they absorb liquids and hold them against your skin.

Foot protection. Steel-toed or composite-toed boots rated to ASTM F2413 are required in any area where heavy components can fall. Oil-resistant outsoles reduce slip risk on shop floors.

Skin and body protection. A shop apron or chemical-resistant coverall protects clothing and skin when draining used oil or coolant. When brake cleaner or other aerosols are involved, a chemical-resistant apron is preferred over a cloth shop coat.

Lockout/Tagout (LOTO) Before Under-Vehicle Work

OSHA 29 CFR 1910.147 governs the control of hazardous energy — electrical, pneumatic, hydraulic, gravitational, and stored mechanical energy. For a parked diesel truck awaiting PM, the relevant energy sources include the engine (can be started), the air brake system (stored pneumatic energy), hydraulic systems (lifted dump body, fifth-wheel slides), and gravity (the vehicle itself rolling).

Six-step LOTO sequence for a shop truck before under-vehicle work:

1. Notify affected employees and the supervisor that the equipment is being taken out of service.

2. Identify all energy sources on this specific vehicle — air reservoir pressure, any electrical circuit, hydraulic circuits.

3. Shut down the engine and place the transmission in neutral or park as applicable.

4. Isolate energy: turn the master battery disconnect to the OFF position; if the vehicle has an air-actuated system you will be working near, bleed down the air tanks per the manufacturer's procedure to a safe working pressure or zero.

5. Apply locks and tags: place your personal LOTO lock on the battery disconnect or the designated energy-isolation point, and hang a tag that identifies you, the date, and the reason for lockout. One person = one lock.

6. Verify zero energy state: attempt to start the engine (it must not crank), confirm parking brake is fully applied, and place wheel chocks — minimum one chock in front of and behind a drive axle tire — before positioning yourself under the vehicle on a creeper.

Remember: a tag alone (tagout) is not equivalent to a lock where a lockout device can be applied. Tags warn; locks prevent.

Hazard Communication and Safety Data Sheets

OSHA's Hazard Communication Standard (HazCom, 29 CFR 1910.1200) requires that every hazardous chemical in the shop have a Safety Data Sheet (SDS) accessible to employees at all times. SDSs follow a standardized 16-section format aligned with the Globally Harmonized System (GHS).

For PM work, three chemicals come up repeatedly:

Used engine oil — classified as a possible carcinogen with long-term skin contact. SDS Section 8 lists nitrile gloves and safety glasses as minimum PPE. Section 13 requires disposal as used oil under EPA regulations; do not pour down drains or mix with solvents.

Ethylene-glycol coolant — acutely toxic if ingested; mildly irritating to skin and eyes. Pressurized systems can spray hot coolant, making face shields important during service. Coolant must not enter storm drains; most shops use a coolant recycling station for reclamation or contract with a licensed waste hauler.

Aerosol brake cleaner (chlorinated or non-chlorinated) — highly flammable in the non-chlorinated form; use away from ignition sources and with adequate ventilation. Chemical-splash goggles are required. The SDS first-aid section will direct you to flush eyes with water for 15 minutes and to move to fresh air if inhaled.

When you read an SDS, always note: (1) the exact PPE in Section 8, (2) first-aid procedures in Section 4, and (3) disposal in Section 13. Record this information on the shop worksheet before handling the chemical — not after an incident.

Putting It All Together

Every PM job follows this sequence: assess the hazards, select and don the correct PPE, complete LOTO before placing yourself in a danger zone, and confirm you know where the SDS is for every chemical you will use. Only then does the wrenching begin. Skipping any step exposes you, your co-workers, and your certification to unnecessary risk.

Key terms10

Personal Protective Equipment (PPE)Clothing and devices worn by a worker to minimize exposure to hazards; examples include safety glasses, face shields, nitrile gloves, and steel-toed boots.
Lockout/Tagout (LOTO)A safety procedure governed by OSHA 29 CFR 1910.147 that uses physical locks and warning tags to isolate hazardous energy sources so equipment cannot be energized while workers are servicing it.
Hazardous EnergyAny source of energy — electrical, pneumatic, hydraulic, gravitational, stored mechanical — that could harm a worker if released unexpectedly during service.
Safety Data Sheet (SDS)A standardized 16-section document required by OSHA HazCom that provides chemical identity, hazard information, PPE requirements, first-aid measures, and disposal instructions for a hazardous substance.
Hazard Communication (HazCom)OSHA standard 29 CFR 1910.1200 that requires chemical manufacturers to label hazardous products and provide SDSs, and requires employers to train workers and keep SDSs accessible.
Globally Harmonized System (GHS)An international framework for classifying and labeling chemicals; OSHA aligned HazCom with GHS to standardize the 16-section SDS format and pictogram labels.
Wheel ChocksWedge-shaped blocks placed against a tire to prevent a vehicle from rolling; required before any under-vehicle work as part of energy isolation.
Zero Energy StateThe condition of a machine or vehicle in which all hazardous energy has been isolated and verified so that no unexpected startup or movement can occur.
Nitrile GlovesChemical-resistant disposable or reusable gloves made from synthetic rubber; the standard hand-protection choice in diesel shops because they resist oil, coolant, and most petroleum solvents and are latex-free.
ANSI Z87.1The American National Standards Institute standard that sets performance and marking requirements for occupational eye and face protection devices, including safety glasses and goggles.
In class: Instructor demo followed by student return-demo: position wheel chocks, apply parking brake verification, and complete a six-step LOTO sequence on a shop truck before sliding under it on a creeper. · Locate and read three Safety Data Sheets (SDS) — engine oil, ethylene-glycol coolant, brake cleaner — and record PPE requirements, first-aid measures, and disposal instructions on a provided worksheet. · Hands-on PPE station: each student selects correct gloves, safety glasses or face shield, and boot protection for three scenario cards (oil drain, cooling system pressure test, parts washing); instructor evaluates each selection.
Materials: Wheel chocks, LOTO locks and tags, SDS binder, nitrile gloves, chemical-splash goggles, face shields, shop aprons, used-oil collection drum, coolant recycling station, OSHA 29 CFR 1910.147 reference card
Check: Instructor safety checklist: student must correctly execute all LOTO steps and select correct PPE for all three scenarios with zero critical errors to pass; any critical error (e.g., missing lockout) = immediate remediation before proceeding.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Safety and Environmental Practices
1. Before sliding under a shop truck on a creeper, a technician completes all six LOTO steps but forgets to place wheel chocks. Which energy source has NOT been adequately controlled?
Safety and Environmental Practices
2. Which OSHA standard specifically covers the control of hazardous energy through lockout/tagout procedures?
Safety and Environmental Practices
3. A student is about to drain used engine oil from a heavy truck. According to typical SDS guidance for used engine oil, which minimum PPE combination is correct?
Safety and Environmental Practices
4. Which section of an SDS tells a technician how to properly dispose of used ethylene-glycol coolant?
Safety and Environmental Practices
5. A technician is about to pressure-test a cooling system on a warm engine. What eye and face protection provides the BEST level of protection for this task?
Safety and Environmental Practices
6. Under OSHA's Hazard Communication Standard, what must an employer do with Safety Data Sheets?
Safety and Environmental Practices
7. During a LOTO verification step, a technician turns the ignition key and the engine cranks and starts. What does this indicate?
Safety and Environmental Practices
8. Non-chlorinated aerosol brake cleaner presents which hazard that requires special attention to the work environment before use?
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