With summer here and hot days upon us, it’s important for precast plants and employees to understand how to safely operate under high-temperature conditions. While staying hydrated and taking breaks is key to worker safety, it’s also essential to consider the impact heat has on the plant and concrete production itself.
After speaking with NPCA’s technical team and referencing OSHA guidelines, here are some key recommendations for keeping both your workforce and your operations safe this summer.
Plant Safety
Hot weather practices may need to be implemented earlier than expected — even under mild conditions. Stay alert to your local weather forecasts and be ready to act accordingly.
Maintain Temperature Control of the Concrete Mix
NPCA’s Quality Control Manual recommends keeping concrete mix temperatures below 90°F. Achieving this may require altering your usual processes. Many plants add ice to the water tank — no more than 75% of the total batch water — and the ice should be crushed, chipped or shaved. For maximum efficiency, the ice should not melt before entering the mixer but must be completely melted before mixing is complete. Some facilities go a step further and use liquid nitrogen to lower the temperature.
Keep Aggregates Cool
Because aggregates make up the majority of concrete’s volume and mass, they greatly influence its temperature. Whenever possible, store aggregates in shaded areas. Sprinkling them with water can also help, but be sure to adjust the mix design to account for the added moisture.
Ventilation
Ventilation is vital in precast plants during the summer, especially in non-climate-controlled environments. Large fans are commonly used to promote airflow and improve comfort, but care must be taken to avoid directing air across fresh concrete, which can cause rapid evaporation and shrinkage cracks. To strike a balance between cooling and moisture control, some plants also use swamp coolers, which add humidity while lowering air temperature.
Employee Safety
According to OSHA, most heat-related illnesses occur during the first few days of hot weather as workers’ bodies adjust. It’s critical to monitor employees closely during this time. Here are a few ways to help workers stay safe in the heat:
Hydration, Hydration, Hydration!
Frequent water breaks are essential. Many supervisors schedule regular hydration breaks to ensure no one forgets to stay hydrated.
Wear Lighter Clothing
Lightweight, breathable clothing can help reduce the body’s heat load. Many employees also use wide-brim hard hat covers or cooling wraps and vests. Whatever choices are made for comfort, proper Personal Protective Equipment (PPE) must still be worn at all times.
OSHA PPE Guidelines
Watch Out for One Another
Encourage all employees to monitor themselves and their coworkers for signs of heat stress or illness. Early recognition is key to prevention.
During the summer months, it’s essential for precast plants to take proactive measures to protect both workers and product quality. High temperatures can pose serious health risks and negatively affect fresh concrete. By implementing the tips above, your plant can stay productive — and safe — all summer long.