Emergency safety showers are a fundamental element in protecting workers in industrial and laboratory environments. However, their effectiveness not only depends on their availability but also on maintaining the correct water temperature to prevent additional skin and body damage.
According to EN 15154 regulations, the water in these showers must remain within a 15-37°C range, with an ideal temperature of 20-25°C. Lower temperatures can cause thermal shock, while higher temperatures increase the absorption of chemicals into the skin.
At Sistemiza, we have developed an energy balance model that efficiently sizes heating systems to ensure a stable supply of hot water in emergency showers. In this article, we explain the main challenges and solutions to optimize these systems.
Challenges in Hot Water Supply for Emergency Showers
Designing a hot water supply system for safety showers presents several challenges:
Maintaining the correct temperature during the minimum 15-minute usage period.
Avoiding thermal fluctuations that may compromise user safety.
Optimizing energy consumption to reduce operational costs while ensuring system reliability.
In many cases, the most efficient solution is using a heated tank with electric resistances, but its design must be precise to avoid energy waste or supply failures.
How to Ensure a Stable Supply: The Energy Balance
To maintain thermal equilibrium in a hot water tank, the following aspects must be considered:
1) Flow Rate (Inlet & Outlet)
Cold water entering the tank must be balanced with hot water output, ensuring a stable temperature.
2) Inlet Temperatures
Network water typically enters cold (between 5 and 15°C), requiring precise energy calculations to reach the optimal temperature.
3) Operation Time
The system must guarantee a continuous supply for at least 15 minutes, the recommended time for effective decontamination.
4) Tank Volume
A well-sized tank prevents sudden temperature drops and allows efficient operation without overloading the heating element.
5) Heating Element Power
The electric resistance must be powerful enough to compensate for heat loss and maintain the ideal water temperature.
Practical Example: Designing an Optimal System
Let’s consider a 3,000 L tank supplying 17 m³/h of water at 22°C, while being refilled with two water streams at 15°C and 5°C.
By evaluating different electric heater power levels, we found the following results:
- 150 kW: Insufficient, temperature drops below 20°C.
- 200 kW: Improves, but still causes thermal fluctuations.
- 250 kW: Optimal, maintains 22°C stably.
- 300 kW: Excessive, uncontrolled temperature increase.
✅ Conclusion: For this case, a 250 kW heater is the most efficient option.
Comparison with Other Heating Systems
Besides using electric resistances, there are alternative heating solutions:
Heat Exchangers: Use external thermal sources (steam or hot water) to heat the tank. More efficient but requires additional infrastructure.
Instantaneous Heaters: Raise the water temperature at the time of use. May cause flow rate and thermal stability issues if not properly sized.
Preheated Tanks: Store preheated water, reducing the electrical heating load.
Benefits of an Optimized Energy Balance
✔ Stable temperature: Complies with regulations and ensures user safety.
✔ Lower energy consumption: Avoids electricity waste from overheating.
✔ Higher reliability: Reduces failure risks in emergency situations.
✔ Lower operational costs: Efficient design minimizes maintenance and energy expenses.
Conclusion
Designing hot water systems for emergency showers is not just about installing an electric heater. A precise energy balance calculation is required to ensure safety, efficiency, and cost savings.
At Sistemiza, we apply our expertise in fluid handling and heat transfer to design optimized solutions for industrial environments.
✍ This article was written by Dr. Javier Sánchez Laínez, Engineering Manager at Sistemiza.
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📩 Contact us at info@sistemiza.com or visit www.sistemiza.com for more information.
#IndustrialSafety #EmergencyShowers #EnergyEfficiency #ThermalEngineering #FluidsHandling #Sistemiza
