- A security fence does not stop a determined intruder; it delays one, and ASTM F2781 measures that delay.
- ASTM F2781 rates fences at three threat levels, Low, Medium and Aggressive, and records the minutes to breach.
- The UK certification scheme is a proprietary, fee based listing program in which one organization writes the standard, tests the product and collects the renewal fees.
- For US projects, specify ASTM F2781 tested fence systems by threat level and delay time, and do not accept an overseas certificate in place of ASTM testing.
- A perimeter is only as strong as its weakest element, so consider gates when you set delay requirements.
ASTM F2781 is the United States test practice for rating how long a security fence resists forced entry. It assigns a threat level based on the tools an attacker may use and records how many minutes the fence holds before it is breached, so specifiers can compare systems on tested delay. This guide explains how the ratings work, why ASTM is the right basis for US projects and the UK certification scheme is not, and how to write ASTM F2781 into a US specification.
Why Forced Entry Delay Matters for a Security Fence
A perimeter fence does not stop a determined intruder. It delays one. Delay turns a detection event into a response opportunity: the minutes between the alarm and the interception are bought, physically, at the fence line.
Yet specifications still describe fence security by height and mesh size rather than tested delay. Two frameworks rate it, ASTM F2781 in the United States and the Loss Prevention Certification Board scheme in the United Kingdom. They are often treated as interchangeable. They are not, and on a US project only one of them belongs in the specification.
What ASTM F2781 Covers
ASTM F2781, Standard Practice for Testing Forced Entry, Ballistic and Low Impact Resistance of Security Fence Systems, is a voluntary consensus test practice maintained by ASTM Subcommittee F14.50 under Committee F14 on Fences. It covers forced entry, ballistic and low impact vehicle resistance, and it was written for comparing fence systems used at commercial, government and military sites.
The forced entry method defines three threat levels by the tools an attack team may carry:
- Low (L): the most limited tool inventory. Power tools of any kind, and devices that take more than one person to carry and operate, are excluded.
- Medium (M): a larger hand tool inventory. Power tools are still excluded, along with devices that take more than two people to carry and operate.
- Aggressive (A): the broadest inventory, and the only level that allows power tools.
Any qualified laboratory can test to the practice. The result documents what the tested fence or gate withstood, against which tools, and for how long.
How to Read an ASTM F2781 Rating
An ASTM F2781 rating pairs the threat level letter with the time to breach in minutes. A rating of A2.2 means the fence was attacked at the Aggressive threat level and resisted for 2.2 minutes before the attack team opened a breach.
Compare ratings within the same threat level, where a higher number means more delay. Across levels, the letter matters as much as the number.
Why the UK Certification Scheme Falls Short for US Projects
The UK intruder resistance standard is owned and run by the Loss Prevention Certification Board (LPCB), a brand of BRE Global. Its current issue grades products by tool category, lettered A to H, and by minimum delay in minutes, set at 1, 3, 5, 10, 15 or 20. A D5 rating, for example, means a single attacker using Category D tools was held for at least five minutes.
It is not just a test method; it is a commercial certification program. Approval requires testing at the scheme’s own laboratory, paid factory audits and a listing that has to be maintained, with fees owed for as long as the certificate is held. The specifier receives a certificate, while the detailed attack data stays with the scheme unless the manufacturer chooses to disclose it.
| Aspect | ASTM F2781 | UK LPCB scheme |
|---|---|---|
| What it is | Consensus test practice | Certification scheme with a maintained listing |
| Threat structure | Three levels: Low, Medium, Aggressive | Eight tool categories, A to H |
| How delay is expressed | Minutes to breach, for example A2.2 | Minimum delay class, for example D5 |
| Who tests | Any qualified, accredited laboratory | The scheme’s own laboratory |
| What the specifier receives | Laboratory test documentation for the tested system | A certificate; detailed attack data stays with the scheme |
| Recurring fees to keep a rating | None | Audit and listing fees for as long as the certificate is held |
| Fit with US specifications | Cited by federal, state and CSI specifications | Foreign scheme rules the project team does not administer |
Who Writes, Tests and Certifies Each Standard
ASTM International is a nonprofit standards body. Its committees are balanced by rule: voting producers may not outnumber voting nonproducers, so a manufacturer cannot outvote the people who use its products. ASTM does not test, certify or license marks, and collects no recurring fee from companies whose products meet its standards.
The UK scheme sits in a different structure. LPCB is part of BRE Group, which grew out of the UK government’s Building Research Establishment, privatized in 1997 and now owned by the BRE Trust, a registered charity. Within that one organization the scheme writes the standard, tests the product, grants the approval, audits the factory and maintains the listing, and each step is a paid service, initially and every year after.
That is the core problem: the organization that decides whether a product is listed earns continuing revenue from the products it lists. Under ASTM, the rule writer, the tester and the manufacturer are separate by design, so no one in the chain is paid to keep a product listed.
What Factory Audits Prove and What They Do Not
In both frameworks the delay rating comes from the attack test, carried out once on a specific tested configuration. A factory audit only verifies that the manufacturer still builds the product the way it built the test article. It adds nothing to the tested strength of the design; what it adds is an annual fee.
A US specifier can get the same production assurance at home: certified mill test reports, weld procedure qualifications, fabrication tolerances and third party inspection where the project warrants it, all written into the specification without an annual certification fee.
Why ASTM F2781 Fits United States Procurement
Federal and state specifications cite ASTM standards as a matter of course, CSI format specifications reference ASTM designations directly, and US laboratories work to ASTM methods. A US specification built on an overseas scheme adds friction: conformance rests on a certificate issued under foreign rules, and enforcing an approved equal at submittal means interpreting a scheme the project team does not administer.
For work governed by US procurement, the enforceable basis is an ASTM designation backed by test evidence for the system being supplied. An overseas certificate is not a substitute, and it should not be accepted as an approved equal.
How to Specify Forced Entry Delay on a US Project
Five clauses cover most perimeter specifications:
- Specify the threat level and the time: timed forced entry testing of the complete fence and gate system to ASTM F2781 at the threat level the risk assessment supports, with delay stated in minutes.
- Ask how the rating was established: which standard, which threat level, what delay time, and whether the tested configuration matches the product being supplied.
- Tie production to the tested article: use drawings and quality clauses to hold installed units to the tested configuration, exactly as with crash rated vehicle barriers.
- Do not accept overseas certificates in place of ASTM testing: a UK delay class cannot be converted to an ASTM F2781 rating, so write the specification so that only ASTM test evidence meets it.
- Consider the whole line: a twenty minute fence with a ninety second gate is a ninety second perimeter.
BSP builds its security fencing in the USA for specifications written to ASTM standards. The family covers anti climb SecureMesh welded mesh, fully bolted SecurePale palisade and the non conductive ENC Security Fence. See the Standards page for the test standards BSP references, and our guide to what drives the installed cost of a high security fence for the budget side.
ASTM F2781 Forced Entry FAQs
What is ASTM F2781?
ASTM F2781 is the US standard practice for testing the forced entry, ballistic and low impact resistance of security fence systems. It rates forced entry delay at three threat levels, Low, Medium and Aggressive, and records the minutes the fence holds before it is breached.
What does an ASTM F2781 rating like A2.2 mean?
The letter is the threat level and the number is the time to breach in minutes. A2.2 means the fence resisted an Aggressive level attack for 2.2 minutes. Compare ratings at the same threat level.
Is a UK LPCB rating the same as an ASTM F2781 rating?
No. The UK scheme uses eight tool categories and fixed delay classes, while ASTM F2781 uses three threat levels and a measured time to breach. They cannot be converted, and a UK certificate should not be accepted in place of ASTM F2781 testing on a US project.
Why should US projects specify ASTM instead of the UK scheme?
ASTM standards are what US federal, state and CSI specifications cite, ASTM is independent of the products it measures, and an ASTM F2781 test produces documentation the project team can review. The UK scheme is a proprietary certification run under foreign rules by the same organization that collects its fees.
Should gates be considered in forced entry planning?
Yes. An intruder looks for the weakest point, and gates and openings are often where delay is shortest. Consider gates when you set delay requirements, and plan detection and response around any opening that delays an intruder less than the fence line.
What should a specifier check in a forced entry rating?
Check which standard the rating comes from, the threat level, the delay time, and whether the tested configuration matches the product being supplied, including its gates.
Specify Delay Rated Security Fencing
Send us the threat level and delay time your risk assessment calls for, and we will recommend the fence and gate system and supply the submittal package to specify it.