Keeping our streets safely lit: Kiwa’s work with lighting columns
When you walk or drive down the street at night, your path is likely illuminated by streetlights. They are so ubiquitous it’s easy to take them for granted: in the UK, there are about 6.5 million publicly owned lighting columns. In order to continue safely lighting our way, these columns need to be inspected regularly to avoid potentially failure and collapse.
“Some columns have actually failed due to corrosion over the years, which has caused injury to the public and damage to cars and other structures,” explained Stephen Spensley, Head of Street Lighting at Kiwa.
“There's a lot of emphasis on health and safety within the lighting sector regarding inspecting and testing, mainly of the aging assets already in situ across the UK and Ireland. By law, there isn’t any requirement to inspect and test lighting columns, but the onus falls on the local authorities or contractors to make sure their assets are safe.”
In July 2022, Kiwa’s team of 15 technicians inspected and tested more than 12,000 lighting columns across the UK and Ireland, helping ensure the safety of people using the public footpaths.
Why do lighting columns need to be tested?
A manufacturer gives a newly produced lighting column a ‘design life’ – it might be 20 years for a steel lighting column, for example – after which it falls into a category called ‘Deemed to Comply’. This means the asset owner becomes responsible for the condition and safety of each column, known as an ‘asset’. A schedule of inspecting/testing is usually introduced at this time to help identify any problems with the existing in situ columns.
Most of the lighting columns Stephen and his team inspect and test are made of steel, which eventually corrodes over time, causing the columns to become dangerous and at risk of failing.
Columns can also be made of other material types, namely aluminum, stainless steel and concrete. Concrete columns are visually inspected for defects like radial and vertical cracks and spalling on the whole column, all of which can cause the columns to become structurally unstable.
“Impact damage on columns Is becoming more and more of an issue,” Stephen said. “The severity of impact damage can again cause the column to be unsafe, and we then recommend replacement.”
Lighting columns also need to be structurally tested if they’re to have additional loadings applied for example, hanging baskets, Christmas decorations, CCTV or banners as this can put additional loads on the column.
For all these columns, the inspection and testing result in a category of 1 to 5, which either means a recommended retest after a certain period of time or a replacement. The speed at which corrosion can occur depends on many factors. For example, columns situated on paths where dog owners frequent, gritting routes, close to the sea and other environments which can affect steel structures.
An Inspection and testing program can help give the asset owner an indication of the expected life span of the columns they maintain. It tracks the deterioration of each asset over time to the point of removal.
How Kiwa inspects and tests steel lighting poles
There are no mandatory regulations for the inspections, but Kiwa works in line with the guidance the Institution of Lighting Professionals (ILP) has set out in the document ILP GN22 Asset-Management Toolkit: Minor Structures (formerly the TR22), for use in the UK.
The technicians use handheld devices to test each column: Relative Loss of Section (RLS), which is used at the base, and Swage Joint Analyser (SJA), which is at the connection between the base and shaft section. Both these instruments quantify levels of corrosion. Kiwa is UKAS accredited for the testing of lighting columns using the RLS and HSJ units.
When the technicians inspect and test lighting columns, they’re looking for corrosion/loss of section at the vulnerable parts of the column, mainly the base. This is detected using the handheld RLS unit, which picks up any corrosion 100mm above and 100mm below ground level. In addition to the testing, a visual inspection is carried out, looking for various levels of corrosion.
Visual inspections range from A to F:
A – Free from defects
B – Loss of paint only
C – Surface corrosion
D – Pitting
E – Extensive corrosion
F – Visible holes
F – Impact damage
When major impact damage has occurred on a column, recommendation is to ‘Replace ASAP’. For all columns that require attention or removal, technicians send photos to the client as supporting evidence.
In any given year, Stephen and the team encounter many dangerous situations. “We've visited columns where sometimes their condition is so bad due to corrosion that the technician waits at the location until the client has sent out a team to cut it down,” he said.
Once testing has been carried out, each column will fall into one of the below recommendations:
Class 1 – 5 year re-test
Class 2 – 3 year re-test
Class 3 – 2 year re-test
Class 4 – Schedule for removal
Class 5 – Immediate removal
Laying the foundation for safety
Each technician aims to visit an average of 50 columns a day, depending on the location, distance between the columns, and crucially, the weather. “Spring and autumn are perfect,” Stephen explained, “but it can be difficult in the heat of summer and the cold of winter.”
Before they can inspect and test the columns, the technicians must first locate them, which is sometimes a challenge in itself. The client – usually a local authority or major contractor – shares the details of the area, street name and secondary location, along with a column number. Occasionally there is no column when the technician arrives, so more investigation is needed regarding the location.
There’s a team of office staff who generate the maps ‘for locations’ on each contract and set up all the relevant site sheets for each job. They are currently working on a new system to have all the historical data for each column pre-loaded on a device, along with real-time mapping systems.
“Steel corrodes at different rates, so testing and inspecting is a continuous cycle over the years, monitoring its deterioration until removal is recommended,” Stephen said.
The team is currently in a period of recruitment. When new technicians join, they undergo mostly in-house training, and audits are carried out before they become ‘competent’. They also require a HERS card for the Highway Electrical Association (HEA) so they can work on the highways, which involves first aid training, manual handling, the G39 electrical awareness course and an Electrotechnical Certification Scheme (ECS) test.
During their training period, which can take up to four months, Stephen says new recruits really get acquainted with lighting columns. After the initial training and courses are complete, the technicians are signed off as ‘competent’ and start inspecting and testing lighting columns. “We encounter a lot of different scenarios and types of columns every day, so it’s a constant learning curve for many years,” Stephen said.