Two of DfL’s lighting designers, Alex Elliot and Paul Southcombe, were tasked with lighting a section of a Newgate Lane, a 40mph B-Road in Fareham, as part of DfL’s Technical Resource Framework contract with Hampshire County Council’s Engineering Consultancy. The work to Newgate Lane forms part of the wider ‘Improving Access to Fareham and Gosport’ project – a strategy that aims to improve access and journey time reliability on the existing arterial routes in the area to support the development of the local economy. The road is a single lane carriageway which had no existing traffic barriers.
A designer risk assessment highlighted a safety issue related to the potential for vehicle collisions with lighting columns. Having explored alternative forms of mitigation through design, the team assessed that passively safe equipment would be required. The equipment was then specified to comply with Passive Safety standard BS EN12767:2007 “Passive safety of support structures for road equipment”, a standard which aims to safeguard vehicle occupants and emergency services at the scene of a road traffic incident. One of the factors which enabled the use of passively safe columns was the fact that the road is surrounded by open land. If this had not been the case, there is a risk that a collision with the passively safe columns could cause injury to pedestrians or damage to buildings.
The unique element of this project was the challenge to design the electrical and maintenance aspects of the passively safe equipment to ensure safety and to reduce maintenance costs. An SIS “Pillar” impact sensor was used in order to detect the force of a collision which then activates the electrical disconnection system using a tilt switch which isolates all circuit within 0.2ms of impact. This is an essential safety requirement to prevent vehicle occupants and emergency service personnel coming into contact with live equipment.
The Maintenance design aspect involved the use of the NAL retention sockets which allow easy replacement of damaged columns.
Columns - SAPA High Energy Passively Safe Columns
Electrical Disconnection System -NAL
Retention Sockets - NAL
The speed of the road and its environment had an impact on the decision as to what equipment was used. Most significant of these considerations was to determine whether the lighting columns should be passively or non-passively safe. The decision was made to use passively safe columns on this project.
NAL retention sockets were specified to reduce maintenance time and cost on removing and replacing columns if they are damaged by a collision as they can be removed in a fraction of the time without the need for excavations thus preventing disruption to road users.
The SIS electrical disconnection system was specified as a safety feature.
Client: Hampshire County Council