What it is
A lightning protection system (LPS) is the network of air terminals, down conductors, earth terminations, and bonding that diverts the energy of a lightning strike safely to ground, preventing damage to the structure, the occupants, and the electrical and electronic systems inside. Lightning protection is a legal requirement on certain building types under building regulations and is industry-standard practice on most commercial buildings of any significant height.
The current standard for lightning protection design, installation, inspection, and maintenance is the BS EN 62305 series, which replaced the older BS 6651:1999. The standard specifies four classes of LPS (I, II, III, IV) reflecting different levels of protection required based on the building’s risk profile, calculated to BS EN 62305-2.
Every lightning protection system requires periodic inspection by a competent person. BS EN 62305-3 Annex E sets out the inspection regime: a visual inspection at least every 12 months, and a full test of the system (including earth resistance measurement) at intervals based on the LPS class and environmental conditions, typically every 11 months for Class I and II systems on commercial buildings.
Our inspection covers the visible system components (air terminals, conductors, joints, fixings, bonds), the continuity of all conductors from air terminal to earth electrode, the resistance of each earth electrode against the design specification (typically below 10 ohms), and the integrity of bonding to all metallic services entering the building. Defects are photographed and logged with their location on a building plan.
When it applies
- Annual visual inspection, required under BS EN 62305-3 Annex E for any installed LPS
- Full periodic test, required at intervals based on LPS class (typically every 11 months for Class I and II)
- After any known direct strike to the building
- After structural works to the building affecting any LPS component
- On acquisition or change of building ownership
- Where an LPS exists but has no current inspection record
The process
- System scope. Confirm system design class, install date, last test date, and any known issues.
- Site visit. Engineer attends with continuity tester, earth resistance tester, and access equipment.
- Visual inspection. Every visible component inspected for corrosion, damage, or detachment.
- Continuity test. Continuity verified from each air terminal to each earth electrode.
- Earth resistance test. Each earth electrode tested against design specification, typically below 10 ohms.
- Bonding test. Integrity of bonds to metallic services verified.
- Certification. Compliant systems receive a 12-month inspection certificate. Defects flagged with remediation quote.
What you receive
- Inspection certificate to BS EN 62305-3 Annex E
- Continuity test record for every conductor run
- Earth resistance reading for every electrode
- Bonding test record
- Annotated building plan showing every tested point
- Photographic evidence of any defects
- Remediation quote for any failed components
- 12-month recertification reminder