This complex and technical project saw Playfords appointed as Principal Contractor, ensuring the works were carried out with all aspects of Health, Safety, Environmental and Quality considered, planning and sequencing the works critical to a successful delivery.
Playfords completed a project at St Thomas’ Hospital where the East Wing Sub-station SS1 infrastructure was operating at its maximum design capacity, which at the time limited new supplies being connected. The East Wing Sub-station SS1 serves critical patient areas and there were a number of key projects lined up that needed supply capacity.
The East Wing Sub-Station comprised of a 1970’s manufactured oil filled switchboard and 3No. High Voltage 11,000 Volt “Oil type” power transformers, located in the lower ground floor of East Wing. The transformers supplied three-sections of low voltage switchboards, all of which dated from the original construction of the building. There are two generators currently supporting the Sub-Station, one of which is a permanently connected generator (EW1) and the other generator (EW2) was connected via temporary type electrical wiring to provide increased standby capacity. The switchboards were at the point with no spare connections available and the capacity requirements were such, that the existing arrangement was not able to support any further development within the East Wing building.
The existing mains infrastructure also contained several significant “Single Points of Failure” (SPF’S) and several HTM non-compliances elements. The existing oil filled transformers were recognised as a significant fire risk, and the electrical loads were such that resilience and redundancy was lost. The ambient conditions were not to the current standards for Sub-Station installations, and with the general age and condition of the electrical equipment, the transformers were de-rated to 90%. Unable to comply with HTM 06-01 Part A, medical areas of Category 4 and 5, which should have dual supplies throughout the system. The requirement for continuous and uninterrupted electrical power for acute healthcare services could not be met with the existing infrastructure.
The East Wing Building had developed significantly since its original construction. This expansion and increase in load on the existing infrastructure was imposing a constraint for further development within the building. Department of Health guidance obligates the Trust to maintain a state of emergency preparedness, ensuring patients, staff and others are protected against the risks of unsafe or unsuitable premises. This requirement could not be guaranteed with the existing infrastructure.
In Summary, the key elements of the project were as follows:
4No. new 1250kVA rated Midel transformers c/w close coupled Schneider RN2C Ring Main Units. The ring main unit circuit breaker now has VIP300 protection. High Voltage Protection Upgrade. New TX1-TX4 LV switchboards. Including new controls cables and DC power supplies. New generator switchboard linking the two generators (EW1 + EW2) and supporting the four sections of low voltage switchboard and associated areas to increase emergency power resilience.
The new infrastructure is also connected to the Hospitals Existing Building Management System (BMS), to enable remote monitoring.
Due to the technical nature of the works and to maintain the Hospital site standards several specialist equipment suppliers, service providers and manufacturers were engaged for the delivery of specific elements of the project.
The project was carried out in a phased manner to ensure hospital service interruptions were kept to a minimum.
The sub-station and Switchrooms now comprise of an HV sub-station containing the 4no 1250KVA transformers with close coupled ring main units. These are connected to 2no HV rings affording additional resilience.