LPS 1175 Explained - Security Ratings, Tools and Resistance Times
A security door can look substantial and still provide less resistance than the response plan assumes. The same applies to fencing, shutters and enclosures.
Descriptions such as “heavy duty” and “high security” do not identify the tools a product has resisted or the delay it can provide. LPS 1175 replaces those broad claims with a measurable classification for resistance to manual forced entry.
The standard is most useful when the rating follows a clear understanding of the protected asset, credible attacker and time needed for an effective response.
Reading an LPS 1175 Rating
Under LPS 1175: Issue 8.2, a Security Rating combines a letter and a number.
Part of the rating | What it represents | Example |
Letter | The tool category used during testing | D |
Number | The minimum working-time delay in minutes | 10 |
A product rated D10 has resisted manual intervention using Category D tools for at least ten minutes of working time under the defined test conditions.
The two parts must be read together. A20 is not automatically superior to D5. A20 represents a longer delay against a lower tool category, while D5 addresses a more capable attack for a shorter period.
Rating selection should begin with the credible attack method and the delay needed before an effective response can intervene.
What Does LPS 1175 Cover?
LPS 1175 is a Loss Prevention Standard used to test and classify the intruder resistance of building components, strongpoints, security enclosures and free-standing barriers.
Products within its scope can include:
Security doorsets, windows, shutters and grilles
Fences and gates
Security cages and enclosures
Access covers and protected openings
Strongpoints incorporated into a structure
The current edition is LPS 1175: Issue 8.2. The official LPS 1175 standard defines the test procedures, tool categories, working times and classifications.
Trained operatives attempt to create an opening, reach a protected area or remove a defined item from the assessed specimen.
The product’s approved hardware and fixing method form part of that evaluated configuration. However, the supporting substrate is assumed to provide resistance at least equivalent to the product, so the surrounding construction must be checked separately.
LPCB certification applies only to the configurations and conditions covered by the certificate. Changes to dimensions, locks, hardware or fixings should not be assumed to retain the same performance.
Tool Categories A to H
The letter in an LPS 1175 rating represents the attack capability used during testing.
The categories progress from lower-technology attacks using small tools to extreme methods involving powered, hydraulic or thermal equipment.
Category | Broad attack profile |
A | Low-technology attack using small, readily concealed tools |
B | More determined attack using hand tools with greater mechanical advantage |
C | Deliberate forced entry using a wider range of commonly available tools |
D | Experienced attack using heavier striking, levering and compact powered tools |
E | Experienced attack using more capable battery-powered equipment |
F | Professional forced entry using heavier equipment and up to two operatives |
G | Enhanced professional attack using high-powered or petrol-driven tools |
H | Extreme portable forced-entry methods, including major cutting, hydraulic or thermal capability |
Categories A to E use a maximum of one test operative. Categories F to H permit up to two. The detailed tool manifest also controls factors such as tool dimensions, power, weight and quantity.
The classification provides a repeatable testing benchmark, not a prediction of an offender’s exact toolkit. Site assessment must still consider attacker capability, concealability, noise and working space.
Resistance Time Is Not Elapsed Time
The number in the rating refers to working time, sometimes called resistance time. It measures the period during which tools are actively used to change or breach the test specimen.
It excludes:
Safety and rest periods
Time spent changing tools
Replacement of defective consumable parts
Inspection time called by the test leader
The standard also sets a longer maximum total duration for each attack test.
Rated working time | Maximum total test duration |
1 minute | 10 minutes |
3 minutes | 15 minutes |
5 minutes | 20 minutes |
10 minutes | 30 minutes |
15 minutes | 45 minutes |
20 minutes | 60 minutes |
A D10 rating does not guarantee ten ordinary minutes from the first strike. It records at least ten minutes of active tool use under controlled conditions.
Installation quality, maintenance, locking condition, attack direction and adjacent construction may all affect real-world performance. The rated delay must therefore be considered alongside how the site detects, verifies and responds to an attack.
Why Issue 8 Changed the Classification
Earlier editions are commonly associated with ratings such as SR1, SR2, SR3 and SR4. Issue 8 introduced a matrix that separates tool capability from resistance duration.
This allows tool threat and delay to be selected independently.
The LPCB guide to changes between Issues 5 and 8 identifies the following retained legacy references:
Issue 8 rating | Legacy reference |
A1 | SR1 |
B3 | SR2 |
C5 | SR3 |
D10 | SR4 |
E10 | SR5 |
F10 | SR6 |
G10 | SR7 |
H20 | SR8 |
An older certified product is not automatically unsuitable, but its certification issue and approved scope must be clear. A specification stating only “LPS 1175 compliant” is incomplete because it does not identify the tool category, resistance time or applicable issue.
Five Decisions Behind the Right Rating
Define the protective requirement before comparing certified products.
1. Identify the Asset
Establish what sits behind the barrier and what would happen if it were compromised.
A perimeter protecting general grounds may require different resistance from an enclosure around operational technology, hazardous materials, critical communications or high-value stock.
2. Define the Credible Attacker
Consider the attacker’s motivation, skill, likely numbers and access to tools.
An opportunist using concealed hand tools presents a different problem from an organised two-person team prepared to use powered equipment.
3. Establish the Response Window
Assess:
Time to detect the attack
Time to verify what is happening
Time to communicate and escalate
Time for an effective response to arrive
Time for responders to reach the protected asset
The delay should reflect realistic out-of-hours conditions. Our discussion of security convergence explains why physical systems, governance and response should be coordinated.
4. Review the Full Attack Path
A certified doorset installed in a weak partition does not create a secure room.
The frame, fixings, supporting wall, glazing, roof, floor, ceiling void and service penetrations all require consideration. An attacker may avoid the certified component and target the surrounding construction.
This is why risk-led physical security design considers the complete route to the asset rather than selecting products one by one.
5. Verify the Certified Scope
Check the certificate during specification and before approving substitutions.
Confirm:
The exact rating and issue
Approved dimensions and configuration
Locks and hardware included in certification
Permitted fixing method and supporting structure
Limitations concerning attack direction or operating condition
Installation and maintenance requirements
The RedBook Live security product listings are the recognised source for checking LPCB-certified products and their listed scope. Product names and marketing brochures should not replace the certificate.
Can LPS 1175 Resistance Times Be Added?
Issue 8 can support layered defence because different barriers may be selected against the same tool category for different delay periods.
BRE’s guidance uses three sequential layers rated F1, F3 and F10 as an example of at least 14 minutes of tested working-time resistance against Category F tools.
For security planning purposes, those times should only be totalled where the design genuinely requires an attacker to defeat each independent layer in sequence.
They should not be added when:
One layer can be bypassed
Products protect alternative rather than sequential routes
Adjacent construction is weaker than the rated barriers
Installation differs from the certified configuration
Detection and response do not cover the complete attack path
Resistance times cannot be totalled simply because several rated products are present on the same site.
What LPS 1175 Does Not Demonstrate
LPS 1175 provides evidence of resistance to the manual forced-entry conditions covered by the certification. It does not establish performance against every security or safety hazard.
On its own, it does not demonstrate:
Ballistic or blast resistance
Resistance to vehicle impact
Fire resistance
General durability
Surreptitious entry or electronic manipulation methods not represented by the defined attack procedures
The effectiveness of CCTV, alarms or guarding
Suitability for a particular site
A guaranteed real-world intervention time
Other standards may be required for those risks. The NPSA’s guidance on protection from forced entry explains why the standard should match the threat, protection level and product type.
Common Specification Errors
Problems often begin before the product reaches the site.
Common errors include:
Naming LPS 1175 without specifying the rating and issue
Treating working time as ordinary elapsed time
Selecting a product before assessing the threat
Assuming the highest rating is always proportionate
Ignoring walls, glazing, roofs or service penetrations
Accepting substitutions without reviewing certification
Using a product outside its approved configuration
Relying on delay without credible detection and response
Failing to inspect and maintain the completed installation
A properly defined rating gives procurement teams a measurable requirement against which certified products can be checked. A certification label alone does not show that the selection is proportionate to the site’s threat or response arrangements.
Establishing the Requirement Through a Physical Security Survey
The relevant question is which rating addresses the credible attack at the point where delay is required.
Our published project experience includes independent scrutiny of physical security design specifications and programme support across multi-site critical infrastructure and other complex environments. This does not mean that Si4 Security tests or certifies products under LPS 1175.
Our Physical Security Survey examines threats, vulnerabilities and risks affecting your critical assets. Depending on the agreed scope, we assess relevant infrastructure, procedures and technology to establish where existing protection may not align with the risk.
The findings can inform later design and specification decisions, including where enhanced forced-entry resistance may be proportionate and which attack routes require closer examination. Product selection and certification should then be verified against the relevant LPCB documentation and approved configuration.
If you need to identify where stronger forced-entry protection may be required, visit our Physical Security Survey service page to see how we can help assess your site’s risks and support a proportionate security strategy.
Turning LPS 1175 into a Defensible Specification
LPS 1175 replaces vague descriptions with a measurable classification of resistance to manual forced entry.
The letter identifies the tested tool category. The number identifies the minimum working-time delay. Neither should be selected without considering the asset, credible attacker, complete attack path and response arrangements.
A defensible specification also checks that the product, hardware, fixings and supporting construction align with the certified scope.
Used correctly, LPS 1175 gives designers and procurement teams a clearer performance requirement. Used as a badge without a risk-led rationale, it may add cost without providing the protection the site actually needs.
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