Retrofitting Central Power Supply Systems (CPSS) in Existing Buildings: Challenges and Critical Considerations for Lift Integration
As the demand for improved energy resilience and compliance with modern safety standards continues to grow, an increasing number of building owners and developers are recognising the value of Central Power Supply Systems (CPSS).
These are crucial in maintaining power to essential equipment in the event of a mains failure - particularly in life-safety applications such as emergency lighting, security systems, fire detection, smoke extraction, and perhaps most critically, passenger lifts and elevators.
However, retrofitting a CPSS into an existing building presents a unique set of technical and logistical challenges. This blog takes a look at these complexities and why overcoming them is vital for safety, compliance and operational continuity.
What Is a CPSS?
A CPSS is a specific type of backup power solution designed for use with emergency and safety-related applications.
Unlike a standard Uninterruptible Power Supply (UPS), a CPSS system is designed to cope with significantly greater overload protection and offers enhanced features for life safety applications.
CPSS must adhere to strict criteria as outlined in the BS EN 50171 standard for use with essential safety systems. This covers emergency applications that are permanently connected to AC supply voltages not exceeding 1000V, that use batteries as an alternative power source.
CPSS systems are more typically used in high-rise or commercial buildings, in healthcare facilities and within public transportation environments.
The Challenges of Retrofitting CPSS into Existing Buildings
Retrofitting a CPSS isn’t as simple as plugging in a backup unit. It involves navigating a range of architectural, electrical, mechanical and regulatory hurdles - each one requiring detailed planning and expert execution.
1. Space and Physical Integration
Many existing buildings lack the space for a CPSS system, particularly those that involve large battery arrays and associated control gear. Understanding the physical environment the CPSS solution will be operating in is therefore key to ensuring optimum performance. It is essential that height and weight limitations, ventilation restrictions and the actual space the unit is to be housed in are all taken into consideration.
This often requires the use of creative engineering solutions such as repurposing plant rooms, installing mezzanines or designing modular CPSS enclosures that can fit into non-traditional areas, while still ensuring full compliance with ventilation and fire safety standards.
2. Load Mapping and Circuit Identification
Identifying and isolating the critical circuits that must be supported by the CPSS, such as lift motors and control systems, can be difficult due to outdated or incomplete building schematics.
Power audits and load testing are therefore essential. Engineers must trace and test each circuit to ensure critical systems can be correctly prioritised and that there is no risk of overloading the CPSS. It is vital that any selected CPSS can handle the total electrical load while also allowing for future growth and expansion. Power Control advises maintaining an additional 20 – 25% capacity to accommodates this purpose.
3. Electrical Infrastructure Compatibility
Legacy distribution boards and wiring systems may not be compatible with modern CPSS units. Retrofitting may involve partial rewiring, upgrading distribution boards or installing power conditioning equipment.
Lift control systems, which can be particularly sensitive to power quality issues, may require tailored CPSS configurations to handle high inrush currents during startup, and variable frequency drives (VFD’s) – which are particularly sensitive to voltage dips and harmonics. Any supporting solution must be carefully sized and capable of handling dynamic load profiles.
Why Overcoming These Challenges Is Critical
Despite the complexities surrounding CPSS retrofitting, it is essential that building owners and developers overcome these challenges for the following reasons:
• Legal Compliance: Adherence to standards such as BS EN 50171 and BS 9999 is mandatory for life safety systems. Failure to comply can lead to legal repercussions, fines and increased liability in case of accidents or injuries.
• Occupant Safety: Emergency lighting and lift functionality during evacuation can be life- saving. Any level of malfunction in the emergency system can potentially endanger building occupants and pose a serious threat to life
• Operational Continuity: For commercial buildings, keeping systems like security, alarms, and communication online during outages is critical
• Insurance and Liability: Properly installed CPSS systems reduce risk, can lower insurance premiums and reduce legal exposure
Conclusion
While retrofitting CPSS into existing buildings presents a significant challenge, especially when integrating complex equipment such as passenger lifts and elevators, it is a necessary investment in safety and compliance. With the right engineering expertise, strategic planning and high-quality equipment, these challenges can be turned into long-term assets for any building.
Power Control Ltd specialises in designing and deploying CPSS solutions tailored to the unique demands of retrofit environments. Our extensive experience with life safety systems and lift integrations ensures we can design and deliver the right solution for your needs that not only meet modern safety standards, but exceed them.
Need support on a retrofit CPSS project? Contact our team to discuss how we can ensure your critical systems never lose power when it matters the most. Call 01246 431431 or email pwc-sales.support@legrand.com