LPS 1175 H20 (SR8) Security Rating Explained

LPS 1175 H20, the Issue 8 rating commonly compared with SR8, is the highest classification in the standard. It certifies that a complete product has resisted an attack with the most powerful tools available short of explosives and firearms for at least twenty minutes, double the ten-minute delay of E10, F10 and G10. It is a maximum resilience rating for the most critical assets in government, defence and national infrastructure. This guide explains what H20 means, how it differs from G10 and SR8, and how to specify and verify an H20 product.

What Does LPS 1175 H20 Mean?

LPS 1175 is the Loss Prevention Standard for intruder resistant building components, published by the Loss Prevention Certification Board (LPCB), part of BRE Global. Every Issue 8 rating has two parts: the letter sets the tools and the attack scenario, and the number sets the minimum delay in minutes the product must achieve. H is the highest tool category and 20 minutes is the longest delay, so H20 sits at the very top of the Issue 8 scale.

At H20, the test team attacks the locked product with Category H tools and must not create a 400 mm x 225 mm opening, the minimum size a person can climb through, within twenty minutes of working time. Any part of the assembly can be targeted, including frames, infill panels, locks, hinges and fixings.

The Category H tool set

Category H represents the maximum resilience scenario in LPS 1175. It builds on everything in Categories A to G, which already includes mains-powered saws and grinders, oxyacetylene cutting, concrete chainsaws, hydraulic jacks and diamond-core drills, and extends to the most powerful tools available short of explosives and firearms. The exact tool list is set out in the standard.

The step to H20 is about time as well as tools. Doubling the delay to twenty minutes against the most capable attack in the standard gives a response force significantly longer to arrive, which is why H20 is reserved for assets where the consequences of a breach are the most severe.

H20 vs SR8: Issue 8 and Issue 7 Explained

LPS 1175 Issue 8 came into effect in 2019 and was the most substantial revision of the standard to date. It replaced the single SR1 to SR8 scale with a tool category letter (A to H) followed by a minimum delay in minutes (1, 3, 5, 10, 15 or 20). H20 is the Issue 8 classification commonly compared with the old SR8, the top of the Issue 7 scale.

The letters shift between the two issues. Issue 7 used an enhanced Category D kit, written D+, for SR5, and Issue 8 turned that kit into Category E. Every tool category above it moved up a letter, so the Issue 7 tool set behind SR8, called Category G, corresponds to Issue 8 Category H. When comparing older documents with new ones, compare the rating, not just the letter.

What H20 Means for Design and Installation

A rating at the top of the standard only delivers its full value inside a protective design built to the same level. Several factors decide whether a twenty-minute delay is achieved in practice:

• Matching structure: the walls, floor slab and roof around an H20 product need equivalent attack resistance. With the most powerful tools in the standard available, any weaker element becomes the route of attack.
• Internal positioning: products at this level usually protect the innermost space of a site, so every outer layer adds delay before the attacker reaches it.
• Controlling equipment and power: heavy tools, generators and supplies have to reach the product. Perimeter barriers, vehicle mitigation and controlled access make that slower and more visible.
• Detection and response: twenty minutes only has value if the attack is detected early and a response arrives within it. Set the rating from the response time in the threat assessment.
• Layered protection: each certified layer keeps its own rating; ratings do not add together on a certificate, but every layer adds delay and another chance to detect the attack.

Where H20 Is Specified

H20 is specified only where a formal threat assessment calls for maximum resilience against the most capable attack the standard recognises. Typical applications include:

• National security facilities
• High-value vaults and bullion stores
• Critical national infrastructure core assets
• Defence and military sites
• Secure government stores
• Specialist high-security installations

In government and critical infrastructure contexts, the threat assessment is typically informed by NPSA (National Protective Security Authority) guidance. It will set the attacker profile, the response time and therefore the rating required for each layer.

Specifying an H20 Product: Checklist

• Confirm the product holds an LPCB certificate showing H20 under Issue 8 (both the letter and the number), and check the current listing on Red Book Live
• Check that the certificate covers the exact configuration, size and opening direction being specified
• Use only the locking systems listed on the certificate; other locks do not carry the rating
• Design the surrounding walls, floor and roof to match the attack resistance of the product
• Detail fixings and the connection to the structure, which sit outside the certificate
• Align the twenty-minute delay with the detection and response plan in the threat assessment
• Specify blast and ballistic resistance separately where explosive or firearm attack is credible
• Plan an uninterrupted power supply for powered locking and access systems if the rating must hold during a mains failure
• Remember that resistance of access control systems to non-mechanical attack is outside the scope of LPS 1175

Frequently Asked Questions: LPS 1175 H20 and SR8

Related Premier Security Resources

• LPS 1175 Security Ratings Explained: the full SR1 to SR8 and A1 to H20 guide
• LPS 1175 G10 / SR7 Rating Guide: the rating below H20
• LPS 1175 F10 / SR6 Rating Guide: the Category F mains-powered tool rating
• Ballistic Resistance: EN 1522 FB and EN 1063 BR ratings explained
• Blast Resistance: ISO 16933, EN 13123 and EN 13541 ratings explained
• Hostile Vehicle Mitigation: protection against vehicle borne threats
• Contact Premier Security: technical consultation and project enquiries