Pfizer, Walton Oaks

Client: Pfizer, Walton Oaks
Name of Project: Arc Flash Risk Assessment Study
Project Completion Date: 2019-11-01

About Pfizer

Pfizer’s UK commercial headquarters are located in Walton Oaks in Surrey.

Opened in 2002, the 320 acre site houses around 700 employees, who work across the biopharmaceutical business or in one of the business support functions (such as finance or HR).

The site also serves as a hub for some of Pfizer’s European business operations.


Electrical Safety UK received an enquiry from CBRE to provide and deliver an arc flash risk assessment at Pfizer’s UK commercial headquarters. CBRE are the facilities management and maintenance team for the Pfizer UK commercial headquarters. The arc flash study was to be carried out in compliance with UK/European Legislation using the benchmark IEEE 1584 and NFPA 70E and to assist them in meeting with the buildings insurers requirements.


Electrical Safety UK carried out a free of charge, on site pre-assessment to determine the extent of the scope of works at Pfizer’s UK commercial headquarters to determine the size of their network. We provided a fixed price proposal for an Arc Flash Risk Assessment Study with project milestones and completion date agreed with the client, with an interim early draft provided within two months to assist the facilities management team.


Electrical Safety UK agreed the scope and strategy with the CBRE facilities management team at Walton Oaks.

Electronic copies of the electrical network single line drawings were provided to Electrical Safety UK to develop the electrical network on our tablet utilising the Easypower® Onsite software prior to the site data collection visit.

We carried out the discovery phase of the work, gathering and verifying information on the electrical distribution system by comprehensively surveying the site’s electrical systems and comparing and modifying the electrical distribution system model where necessary on our tablet.#

The data collected and verified during the site data collection process with our tablet and EasyPower® Onsite software was downloaded into our EasyPower® modelling software.

An early interim draft of the arc flash study was provided to the facilities management team two months after the initial site data collection and verification visit in line with the arc flash study requirements.
Following verification and provision of outstanding data a full arc flash analysis was carried out on the Pfizer, Walton Oaks site electrical system, which including:

• short circuit analysis
• simple protective device co-ordination
• arc flash incident energy
• arc flash boundary distance

The site was supplied from the UK Power Networks 11kV system.
Any instances where the 3-phase prospective short circuit current exceeded the breaking capacity of protective devices was highlighted in the report. Protection device time-current characteristic curves showing any instances of miscoordination were provided. Incident energy levels and arc flash boundary distances were listed for all equipment included in the scope of the study.

Up to date single line diagrams for the electrical network were provided to facilities management team that included Site Data, Fault Study and Arc Flash Study Analysis.

Incident energy hazard reduction analysis was then carried out and preferred options and order of magnitude costs were given for the reduction of the incident energy where it was above 8 cals/cm2.

Electrical Safety UK presented the Arc Flash Report via video conferencing with the CBRE Team at the Walton Oaks site.

Arc Flash labels to the UK/European standard were issued for application to the electrical equipment switchgear and enclosures.

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