Case Study: Hybrid Fire Alarm Upgrade at Nutmeg House, Tower Bridge
Project Overview
Electrifire was appointed to upgrade the fire alarm system at Nutmeg House, 60 Gainsford Street, London SE1 2NY, an occupied office building located within a five-minute walk of Tower Bridge.
The building’s existing hybrid fire alarm system had become obsolete. It was built around a Notifier fire alarm panel, with Notifier hard-wired devices installed in the common areas and Hyfire wireless devices used across the occupied tenant floors.
Because Nutmeg House remained fully occupied and featured exposed ceilings and high-quality decorative finishes, replacing the system with a fully hard-wired installation would have caused significant disruption.
The building consultant therefore specified another hybrid system. This would maintain hard-wired fire detection within the common areas while using wireless devices throughout the tenant spaces.
Electrifire developed and installed a compliant replacement system comprising an Advanced MxPro 5 fire alarm control panel, Apollo XP95 hard-wired devices and EMS FireCell wireless devices.
The £73,000 project was completed within seven working days on site.
The Challenge at Nutmeg House
Replacing a fire alarm system within an occupied, multi-tenanted office building required careful planning and close coordination.
Businesses needed to continue operating throughout the installation, while exposed ceilings and high-quality decorative finishes restricted the scope for intrusive cabling works.
The existing system included:
- A Notifier fire alarm control panel
- Notifier hard-wired devices within the common areas
- Hyfire wireless devices throughout the tenant floors
- Existing fire alarm cabling
- Interfaces with essential building services
As the original system had become obsolete, the building consultant produced a specification for a complete fire alarm upgrade.
The replacement needed to provide modern and reliable fire detection while preserving the hybrid arrangement best suited to the layout and occupation of the building.
It also needed to integrate correctly with the access control system, smoke ventilation, lifts, gas supplies and relevant plant equipment.
Reviewing the Consultant’s Fire Alarm Design
The original specification required a Category L2 fire alarm system.
Before installation began, Electrifire completed a detailed design review to establish whether the proposed detection coverage and system interfaces would satisfy the required standard and the building’s wider fire strategy.
The review identified several additional measures needed to complete the design, including:
- Additional detection across all escape routes
- Detection within rooms opening onto escape routes
- Detection within areas presenting a specific fire risk
- Additional visual alarm devices in toilets and shower rooms
- Further interfaces with essential building services
Completing the design review at an early stage allowed the additional requirements to be incorporated into the installation programme. This avoided the risk of deficiencies being identified after the new system had already been fitted.
Electrifire is BAFE SP203 accredited for the design, installation, commissioning and maintenance of fire detection and alarm systems. Each installation begins with a review of the building, its use and the applicable fire strategy.
A Hybrid Solution Designed Around the Occupied Building
Electrifire selected an Advanced MxPro 5 fire alarm control panel as the basis of the new system.
Suitable existing cabling was retained and reused where possible, reducing the amount of new cabling required within the building.
The original Notifier hard-wired devices were replaced with Apollo XP95 devices across the common areas. EMS FireCell wireless devices were installed throughout the occupied tenant floors, replacing the existing Hyfire equipment.
Using wireless detection within the tenant areas avoided the need to install extensive new cabling through completed office spaces and exposed ceilings.
The completed hybrid system included:
- An Advanced MxPro 5 fire alarm control panel
- Existing fire alarm cabling reused where suitable
- Apollo XP95 hard-wired devices within the common areas
- EMS FireCell wireless devices across the tenant floors
- Additional detection identified during the Category L2 design review
- Visual alarm devices within toilets and shower facilities
- Interfaces with essential building systems
This combination provided a modern replacement for the obsolete Notifier system and its associated Hyfire wireless devices, while maintaining the practical advantages of a hybrid fire alarm system.
Integrating the Fire Alarm with Building Services
The new fire alarm system at Nutmeg House needed to do more than activate audible and visual warning devices.
Electrifire installed and configured the additional interfaces required to ensure that connected building systems responded correctly when the fire alarm was activated.
The completed cause-and-effect arrangements included:
- Releasing access-controlled doors
- Opening the Automatic Opening Ventilation system
- Returning lifts to ground level
- Shutting down gas supplies
- Shutting down relevant plant equipment
These interfaces form an important part of the building’s overall evacuation procedures and fire strategy.
Testing the interfaces confirmed that the full sequence operated as intended, including door release, AOV operation, lift grounding and the activation or shutdown of connected systems.
Completing the Works in Seven Working Days
The installation programme was carefully planned around access to the building’s common areas and occupied tenant floors.
Clear communication between Electrifire, the landlord, consultant, building management team and tenants helped ensure access could be arranged efficiently and any concerns addressed promptly.
Using EMS FireCell wireless equipment within the tenant areas significantly reduced the amount of intrusive work required.
As a result, Electrifire completed the on-site installation within seven working days while maintaining minimal disruption to the businesses operating from Nutmeg House.
The team also completed the required making-good works on behalf of the landlord, leaving areas affected by the installation with an appropriate decorative finish.
Testing, Commissioning and Independent Inspection
Once the system had been installed, Electrifire completed a thorough testing and commissioning process.
The completed fire alarm system was demonstrated to the consultant, including the operation of the Advanced MxPro 5 panel and its interfaces with the building’s other safety systems.
A BAFE auditor also inspected the installation, providing independent oversight of the completed system and the work delivered.
Electrifire’s BAFE SP203 approval covers all key stages of fire alarm delivery, from design and installation through to commissioning and ongoing maintenance.
Complete Fire Alarm Documentation
A full Operation and Maintenance pack was prepared for the landlord at the end of the project.
The handover information included:
- As-fitted fire alarm drawings
- Fire alarm zonal drawings
- System operating information
- Details of the installed equipment
- Testing and commissioning records
- Relevant certification and supporting documentation
This provided the landlord and building management team with an accurate record of the new fire alarm system, together with the information required for future testing, maintenance and compliance activity.
The Outcome
Electrifire successfully delivered a complete hybrid fire alarm upgrade at Nutmeg House, including:
- Replacement of the obsolete Notifier system incorporating Hyfire wireless devices
- Installation of an Advanced MxPro 5 fire alarm control panel
- Installation of Apollo XP95 hard-wired devices
- Installation of EMS FireCell wireless devices
- Reuse of suitable existing fire alarm cabling
- A full Category L2 fire alarm design review
- Additional detection across escape routes and higher-risk areas
- Visual alarm devices within toilets and shower rooms
- Integration with access control doors, AOVs, lifts, gas supplies and plant equipment
- Completion within seven working days
- Minimal disruption to occupied offices
- Making-good works completed for the landlord
- A complete O&M pack with as-fitted and zonal drawings
- System demonstration to the consultant
- Independent inspection by a BAFE auditor
A Practical Upgrade for a Complex Occupied Site
The project at Nutmeg House demonstrates how an obsolete fire alarm system can be replaced within an occupied commercial building without compromising decorative finishes or creating unnecessary disruption.
By retaining suitable existing cabling and combining Apollo XP95 hard-wired devices with EMS FireCell wireless technology, Electrifire delivered a modern hybrid fire alarm system designed around the layout, occupation and operational requirements of the building.
The result was a compliant Category L2 solution, completed within a tightly controlled programme and fully integrated with the wider fire safety systems at Nutmeg House.