Life support
Ed Haslett, Divisional Director – Critical Facilities UK & Ireland at Zumtobel Group, says it is time to rethink data centre emergency lighting for increased reliability of life-critical systems.
Amidst the complexity of cooling system and IT infrastructure, life-critical emergency lighting systems often remain an afterthought when fitting out a data centre. Yet strategic planning from the outset can profoundly impact reliability, operational efficiency and, most importantly, safety. The biggest question is whether to opt for a centralised power system.
With cooling accounting for approximately 40% of a data centre’s energy consumption, heat and overheating are major concerns. Efficiency is not only pivotal for profitability but also for mitigating the costs associated with downtime due to overheating.
Moreover, the higher ambient temperature in data centres can also adversely affect emergency lighting systems, compounding data centre operators’ challenges.
But let’s take a step back and look at the role of emergency lighting to understand the gravity of this predicament.
The role of emergency lighting
When standard lighting fails, emergency lighting is the lifeline that provides sufficient illumination to give orientation and efficiently light an escape route. It prevents panic and ensures that other safety equipment can be found immediately. In a nutshell, it can be lifesaving. Emergency lights are designed to activate immediately when the electricity supply fails; the batteries take over and power luminaires for one, three, or eight hours.
Why traditional emergency lighting systems are challenging
In the demanding environment of data centres, ambient temperatures in hot aisles often range from 35-45°C. Here, the operational limitations of integral battery emergency luminaires become evident. The specified operating temperatures for many of these conventional emergency luminaires typically cap at 25-30°C, highlighting a substantial performance gap. Manufacturers may sometimes indicate higher operating temperatures, but it is crucial to distinguish between the case temperature of the emergency kit itself and the tested operating temperature within a luminaire. The elevated ambient temperatures pose a significant challenge for the integral batteries within emergency luminaires.
Understanding ambient temperature (Ta)
Ta, or ambient temperature, is a critical factor influencing the performance of emergency lighting systems. In the confined spaces of a luminaire, the Ta inside the fitting is affected by various heat sources, including the driver, emergency converter, charging batteries and the LED board. With data centres trying to optimise floor space and pack in more servers, temperatures are rising; the Ta inside luminaires can escalate rapidly, surpassing the operational limits of integral battery systems.
The case for centralised power systems
Centralised emergency power systems offer a compelling solution to this challenge. These systems ensure consistent operation even in extreme (higher temperatures) conditions by eliminating reliance on integral batteries. Moreover, they reduce maintenance demands and costs associated with frequent replacements. The white space, especially, is often a highly secure area within the data centre building, so limiting access, unless absolutely necessary to interfere with it, is in the client’s best interest.
Having the busy data centre and facilities management teams repeatedly return to areas to maintain the life safety systems and change out emergency lighting components is not only a poor use of their time, but it also introduces more visits to these highly sensitive spaces. A central battery system centralises the components so that they can be located in areas of lower temperature and away from the more sensitive spaces through good design practice. A bonus is that these systems’ battery life can be guaranteed longer than that of integral battery options.
Best practices for design and implementation
A best practice design comprising LED lighting technology, an intelligent lighting control system and a central power system (CPS) to support a dedicated emergency lighting system will positively impact energy usage. In addition, it will reduce associated manual maintenance costs whilst creating a safer, more flexible lighting solution that can be quickly and easily adapted to suit changing requirements.
Emergency central battery systems using dedicated emergency luminaires can reduce emergency lighting loads and the number of emergency lighting circuits. This leads to a more cost effective initial installation and an easier system to maintain long-term. As a general rule of thumb, once more than 120 emergency luminaires are present on a project, the DC central battery system often pays for itself.
A tailored lighting strategy based on cooling topologies within data centres is advised. For hot aisles, a Ta 45-rated lighting system with dedicated emergency luminaires fed from a central battery system is recommended. In cold aisles and circulation areas, a high Ta-rated luminaire will not be required, but a coordinating solution can be applied.
Proactive monitoring for enhanced safety
Beyond physical infrastructure, proactive monitoring of emergency luminaires is crucial. Intelligent systems continuously assess performance, alerting operators to potential issues before they escalate. This proactive approach minimises downtime and maximises system lifecycles, bolstering safety and operational efficiency.
Automating testing and maintenance
To ensure fail-safe performance, a dedicated, addressable emergency lighting system with full automation of testing is required. Cutting-edge technology enables automatic system status reporting, reducing human error and maintenance costs. Remote supply systems further support higher ambient temperatures, ensuring system resilience.
Enhancing reliability and safety
By embracing centralised supply systems and proactive monitoring, data centres can bolster emergency lighting systems’ reliability, safety and operational efficiency. A considered approach to emergency lighting provides a critical safety net for personnel and infrastructure, ensuring uninterrupted operation even in challenging environments.
In the dynamic landscape of data centres, where every second counts, prioritising emergency lighting is not just prudent – it’s essential. With innovative solutions and strategic planning, data centres can confidently navigate challenges, safeguarding people and technology.
