Heat Stress Exposure Control Plan
Overiew
Heat stress occurs when the body is unable to cool itself adequately, leading to a rise in core body temperature. Exposure to extreme heat can result in heat rash, heat cramps, heat exhaustion, and fatal heat stroke. Heat stress can occur both indoors and outdoors. Crane operators and workers on construction sites face particular risk due to prolonged outdoor exposure, physical exertion, and limited shade. Under WorkSafeBC Occupational Health and Safety Regulation (OHSR) Part 7, Section 7.29: Heat Stress Assessment and Exposure Control Plan, employers must conduct a heat stress assessment and develop and implement an Exposure Control Plan (ECP) in accordance with OHSR Part 5, Section 5.54(2) whenever workers may be exposed to heat stress conditions.
Safety Alert
Contact with extreme heat may result in heat rash, heat cramps, heat exhaustion, and/or fatal heat stroke. Heat stress can occur both indoors and outdoors when the body heats up faster than it can cool itself. If not recognized and treated early, heat stress can lead to serious heat disorders, cardiac arrest, and other life-threatening injuries.
Required Elements of a Written Heat Stress Exposure Control Plan
A compliant written plan should include the following:
- Policy statement: State management’s statement of commitment to heat illness prevention.
- Plan scope: Identify the plan’s covered worksites, operations, and workers.
- Roles and responsibilities: Identify who does what. E.g., supervisors, workers, safety personnel
- Heat stress monitoring: List methods used. E.g., Wet-Bulb Globe Temperature (WBGT) measurements, heat index tracking, weather forecasting protocols
- Acclimatization program: Detail the ramp-up schedule for new and returning workers.
- Hydration program: Outline water provision, access, and schedule.
- Work-rest schedule: Outline a schedule tied to WBGT / metabolic load.
- Engineering and administrative controls: List controls such as shade and cooling provisions and/or shift adjustments.
- Clothing and PPE: Identify what is used and if any Threshold Limit Value (TLV) corrections are applied.
- Training requirements: Outline what workers and supervisors must know and what training is provided.
- Emergency response procedures: Detail available first aid, 911 protocols, identify the nearest hospital, and list available cooling equipment.
- Medical surveillance: Document pre-placement exams and return-to-work procedures after heat illness.
- Recordkeeping: Keep incident logs, training records, and monitoring data.
Reminder
The hazard assessment must review all contributing factors such as environmental conditions, physical demands, worker susceptibility, and the effect of PPE. Exposure control plans must be specific to each worksite and workforce and must be reviewed and updated regularly as conditions change.
Assess the Hazard
Perform a hazard assessment before starting work in hot environments to identify potential risks and implement appropriate controls. As required by Occupational Health and Safety (OHS) Guideline G7.29-1 Heat Stress Assessment, the heat stress assessment must:
- Identify heat hazards. Evaluate the work zone for environmental conditions including air temperature, radiant heat, air movement (or lack thereof), and relative humidity. Radiant heat sources include sun exposure, reflected heat from roofs or paved surfaces, and indoor sources such as boilers and engines.
- Assess physical demands. The harder a person works, the more heat the body produces. Heat stress can occur at lower air temperatures if the work is physically demanding. Work rate is a key factor in crane assembly, load handling, and rigging tasks.
- Consider worker-specific factors. Evaluate individual susceptibility for hydration level, physical fitness, obesity, medical conditions, prescription drug use, and acclimatization status. Workers new to a hot environment or returning after seven or more days away are considered unacclimatized and face greater risk.
- Review the effect of PPE. Certain PPE, including high-visibility vests, harnesses, and hard hats, can impede the body’s ability to cool itself, increasing heat stress risk, and accommodations may need to be made.
- Use a heat stress screening tool. WorkSafeBC provides an online Heat Stress Screening Tool to evaluate when workers are at risk and when controls must be implemented. Use the Wet Bulb Globe Temperature (WBGT) or the Humidex methods as acceptable assessment methods.
Hierarchy of Controls
Always apply controls in order from most to least effective:
| 1: Elimination / Substitution | Reschedule heat-intensive work to cooler hours, such as in the early morning or at night. Use mechanical assistance to reduce work intensity. |
|---|---|
| 2: Engineering Controls | Use air conditioning, shade structures, cool rest areas, cool water delivery systems, radiant heat shielding, and ventilation. |
| 3: Administrative Controls | Use work-rest regimens, shift scheduling, buddy systems, pre-shift briefings, acclimatization programs, and a reduced work pace. |
| 4: Personal Protective Equipment | Use cooling vests, moisture-wicking clothing, and water-cooled garments. Use cooling PPE only when other controls are inadequate as PPE can increase WBGT if impermeable. |
Eliminate the Source
The first and most effective option is to eliminate the heat hazard. Engineering controls should be introduced first wherever practicable as per OHSR Section 7.30 Heat Stress Controls.
Cancellation or Postponement
Cancel or postpone work until heat conditions improve, if operationally feasible.
Air Conditioning or Spot Cooling
Provide air conditioning in site trailers, crane cabs, or rest areas. Install local spot coolers near workers performing high-demand tasks.
Shielding or Insulation
Cover or insulate hot surfaces such as crane components and metal decks. Add shading structures to reduce radiant heat exposure.
Ventilation
Use fans or other means to improve air movement and remove hot air from enclosed cab or work areas. Note: fans may not be effective above 35°C.
Maintain Safe Conditions (Engineering and Administrative Controls)
Where the hazard cannot be fully eliminated, administrative controls and safe work practices are required under OHSR Section 7.30 Heat Stress Controls and OHS Guideline G7.30 Heat Stress Controls:
Work‐Rest Cycles
Establish appropriate work-rest cycles based on temperature, humidity, and work intensity. Rest breaks must be scheduled proactively. By the time a worker feels ill, it may already be too late.
Scheduling
Perform strenuous physical work during the coolest parts of the day (before 11:00 am and after 3:00 pm). Allow a slower work pace during the hottest periods.
Hydration
Provide ready access to cool drinking water near the work area. Workers should drink approximately two glasses (0.5 litres) before starting work and one glass every 20 minutes throughout the shift. Alcoholic and caffeinated beverages are not recommended.
Cooling Areas
Establish cooling areas with shade and water that are readily accessible to all workers. Showering or soaking in cool water can cool the body quickly.
Work Rotation
Rotate work activities or assign additional workers to reduce the duration of heat exposure for any individual.
Buddy System and Monitoring
Require that workers do not work alone in hot conditions. Implement a buddy system to watch for signs of heat stress. Monitor thermal conditions throughout the day, as outdoor conditions can change rapidly.
First‐Aid Coverage
Ensure adequate first-aid coverage and emergency procedures are in place and understood by all workers. If administrative controls are insufficient to keep workers safe, stop work until conditions improve.
Preventing Heat-Related Illness
After hazard identification and risk assessment, if workers could still be exposed to heat stress conditions, the following precautions must be followed:
- Conduct a planning meeting with all workers in the hot work area to review identified heat hazards, signs and symptoms of heat-related illness, and steps that will be implemented to prevent heat stress.
- Develop and enforce specific safe work procedures for working in hot environments. Ensure all personnel understand the emergency response plan.
- Engage workers in daily discussions about heat-related hazards at the start of each workday.
- Empower workers to speak up when they feel it is unsafe to work in a heated environment. All workers have the right to refuse unsafe work.
- Determine acclimatization status of all workers. Implement a gradual exposure schedule of 7 to 14 days for workers new to hot environments or returning after seven or more consecutive days away.
- Train workers to recognize early signs of heat exhaustion and heat stroke.
- Maintain clear communication with supervisors and first-aid personnel.
Additional Safety Measures
Further safety measures may be used to enhance protection, especially for high-demand tasks in hot conditions:
- Light-coloured, breathable clothing
Have workers wear light-coloured, loose-fitting clothing made of breathable fabric such as cotton, where PPE requirements permit. - Personal risk factors
Workers must be aware of individual factors that increase susceptibility: certain medications (e.g., diuretics, antihistamines, beta-blockers), lack of sleep, cardiovascular or metabolic conditions, and pregnancy. - Personal cooling devices
Cooling vests worn under PPE may help maintain safe body core temperature. Portable fans or misting devices may be used during rest breaks.
Emergency Procedures
Recognizing Signs and Symptoms
Workers must be trained to recognize the signs and symptoms of heat-related illness in themselves and co-workers:
| Condition | Signs and Symptoms | Treatment |
|---|---|---|
| Heat Rash | Rash or worsening of existing skin problems, intense itching, prickly sensations | Leave the hot environment until the rash heals. Keep affected areas clean, cool, and dry. |
| Heat Cramps | Muscular pain or spasm, or excessive sweating | Move to cooler area, loosen clothing, sponge with cool water, provide oral fluids if fully alert. |
| Heat Exhaustion | Shallow/increased respiration, weak, rapid pulse, cool, pale, clammy skin, sweating, weakness, dizziness, fatigue, headache, nausea, fainting, or muscle cramps. **The presence of sweating differentiates heat exhaustion from heat stroke. | Move to a cooler area, lay down, loosen clothing, sponge with cool water and fan, and provide oral fluids if fully alert. Transport to receive medical aid. |
| Heat Stroke MEDICAL EMERGENCY | Hot, dry, and flushed skin, absence of sweating, agitation, confusion, decreased consciousness, headache, nausea/vomiting, seizures, increased respiratory rate, irregular pulse, shock or cardiac arrest | Call 911. Move to the coolest place, remove outer clothing, apply cold water over the entire body, fan continuously, and maintain airway. Do not give fluids if unconscious. Continue cooling during transport. |
Source: WorkSafeBC Heat Stress Screening Tool
Emergency Response
Ensure that adequate first-aid supplies and trained first-aid attendants are available whenever workers are exposed to heat stress conditions.
Use the treatment actions in the table above. If symptoms worsen or do not improve within 30 minutes, seek immediate medical attention.
Heat stroke is serious. Be sure to notify the first aid attendant, call 911, and arrange for immediate transportation to medical aid.
References and Resources
OHS Regulation Requirements
- OHSR Section 7.27–7.32 Heat Exposure
- OHSR Section 5.54 Exposure Control Plan
OHS Guidelines
- OHS Part 7, Guideline G7.27(1) Heat Exposure – Application
- OHS Guideline G7.28(1)-1 Heat Stress Exposure Limits
- OHS Guideline G7.28(1)-2 Unacclimatized Workers
- OHS Guideline G7.29-1 Heat Stress Assessment
- OHS Guideline G7.29-5 Exposure Control Plan
- OHS Guideline G7.30 Heat Stress Controls
- OHS Guideline G7.31 Provision of Water
Information in this document is considered accurate at the time of publication. Please contact BC Crane Safety with any questions or recommendations for content revision.
