White Paper · Security Fencing
Vehicle barriers get the attention. The fence line does most of the work. This paper compares the two frameworks used to rate forced-entry delay in security fencing — and what each one actually tells a United States specifier.
A perimeter fence does not stop a determined intruder; it delays one. Delay is what converts a detection event into a response opportunity — the minutes between an alarm and an interception are purchased, physically, at the fence line. Yet while vehicle barrier crash ratings are widely discussed, forced-entry delay ratings for fencing remain poorly understood in the United States market, and specifications routinely describe fence “security” by height and mesh dimensions rather than by tested delay performance.
Two frameworks exist to fill that gap: ASTM F2781 in the United States and LPS 1175 in the United Kingdom. They are frequently presented as interchangeable. They are not — in test philosophy, in classification, in institutional structure, and in enforceability under US procurement.
ASTM F2781, Standard Practice for Testing Forced Entry, Ballistic and Low Impact Resistance of Security Fence Systems, is a voluntary consensus test practice developed by Subcommittee F14.50 (High Security Fences and Perimeter Barriers) of ASTM Committee F14. It defines tool inventories for three escalating threat levels — with power tools excluded from the lowest — and a method for timed attack testing of fence and gate systems, producing delay results against each threat level. Testing to F2781 is performed by laboratories; the output is a test report documenting what the tested article withstood, for how long, against which tools.
LPS 1175, Requirements and testing procedures for the LPCB approval and listing of intruder resistant building components, strongpoints, security enclosures and free-standing barriers, is a Loss Prevention Standard owned and administered by the Loss Prevention Certification Board (LPCB), part of the BRE Group. Its current Issue 8 classifies products by a two-part code: a letter, A through H, identifying the toolkit used in the attack, and a number — 1, 3, 5, 10, 15, or 20 — stating the minimum delay in minutes (for example, C5 or D10). LPS 1175 is not only a test method: it is a certification scheme. Approval requires testing at BRE, ongoing factory production control audits, and maintenance of a listing in LPCB's Red Book, each element carrying fees payable to the certification body for as long as the certificate is held.
| ASTM F2781 | LPS 1175 (Issue 8) | |
|---|---|---|
| Instrument type | Consensus test practice; output is a laboratory test report | Proprietary certification scheme; output is a maintained certificate and Red Book listing |
| Threat structure | Three threat levels defined by tool inventories (hand tools at the lowest level; power tools excluded there) | Eight tool categories (A–H) of escalating capability, including battery and powered tools at upper categories |
| Delay expression | Timed resistance against the threat-level tool set, with test durations up to 15 minutes | Minimum delay classes of 1, 3, 5, 10, 15, or 20 minutes paired with the tool category |
| Who tests | Any qualified laboratory working to the practice; specifier requires independence and accreditation in the specification | BRE's own laboratory, as part of the LPCB approval process |
| Evidence available to the specifier | The full test report: tools, attack sequence, times, failure modes, tested configuration | The certificate and listing; the detailed attack data remains with the scheme unless the manufacturer discloses it |
The two frameworks are produced by organizations with fundamentally different structures, and a specifier evaluating third-party evidence should understand both.
ASTM International is a nonprofit standards development organization. Its standards are written in open committees balanced by rule: members are classified as producers, users, consumers, and general interest, and producers are capped at no more than half the vote of any subcommittee — a manufacturer cannot outvote the users of its own products. ASTM sells documents and membership; it does not test products, certify products, license marks to fence manufacturers, or collect recurring fees from companies whose products meet its standards. It has no financial relationship with any manufacturer contingent on a product passing or failing, and no listing whose renewal generates revenue.
LPS 1175 is owned by LPCB, a brand of BRE Group Limited — the commercial company created when the United Kingdom privatized its national Building Research Establishment in 1997. BRE Group is in turn owned by the BRE Trust, a registered UK charity that applies the group's profits to built-environment research. Within this structure, LPCB operates as a commercial certification body: it writes the standard, performs the testing, grants the approval, audits the factory, and maintains the listing — and each stage is a service for which the manufacturer pays, initially and annually. This is a conventional and openly published certification-scheme model, and LPCB's marks are respected internationally. But the structural fact remains: the organization that decides whether a product is listed derives continuing revenue from the population of listed products. Under the ASTM model, the standard's author has no such relationship; independence between the rule-maker, the tester, and the manufacturer is inherent to the architecture rather than managed within one organization.
LPS 1175 is a United Kingdom scheme. Its heritage is the UK insurance loss-prevention world; its testing is performed in the UK; its ratings are embedded in UK government security guidance and are specified across the UK and parts of Europe and the Middle East. Within that ecosystem it functions as the native benchmark.
United States procurement runs on a different chassis. Federal and state specifications cite ASTM standards as a matter of course; CSI-format specifications reference ASTM designations natively; US test laboratories work to ASTM methods; and F2781 was developed with US military, homeland security, and utility users at the table. A US specification built on an overseas certification scheme inherits practical friction at every step: the standard must be purchased from a foreign body, conformance depends on a certificate issued under UK scheme rules rather than a report the specifier can review, re-testing or configuration changes route through one laboratory in another country, and enforcement of a “certified equal” during submittals becomes an exercise in interpreting a scheme the project's engineers do not administer. None of this reflects on the quality of UK-certified products. It is a statement about fit: for work governed by United States procurement, the enforceable currency is an ASTM designation supported by a lab report.
The most misunderstood difference between the frameworks is LPS 1175's ongoing audit requirement. Under the LPCB scheme, certificated manufacturers receive periodic factory production control audits, and the certificate's continuation depends on them (and on continued scheme fees). Under the ASTM model there is no surveillance component: the test report documents the tested article, and the specification ties production units to the tested configuration through ordinary submittal and quality clauses.
It is important to state precisely what each element proves. The delay rating — in both frameworks — is established by the attack test, once, on a specific tested configuration. A factory audit verifies that the manufacturer continues to build the product the way it built the test article. That is a legitimate assurance function, but it adds nothing to the demonstrated strength of the design: an audited C5 fence and an unaudited fence built to an F2781-tested drawing package have both proven their delay exactly once, in a laboratory attack. A specifier can obtain the same production assurance domestically through standard means — certified mill test reports, weld procedure qualifications, fabrication tolerances on the drawings, and third-party inspection where the project warrants it — without routing it through the certifier's annual fee cycle. What the audit model does do is bind the assurance function and its recurring cost to the certification body itself; the specifier should understand that this is a commercial design of the scheme, not an increment of tested performance.
ASTM F2781 and LPS 1175 both bring engineering discipline to a question the market has answered with marketing for too long: how many minutes does the fence actually buy? They are not, however, interchangeable. One is an open consensus test method whose evidence is a report the specifier can read, written under rules that structurally separate the standard's author from the products it measures. The other is a well-established but proprietary overseas certification scheme in which authorship, testing, approval, and recurring revenue reside in a single commercial organization. For United States projects, the specification should stand on the framework its procurement system can enforce — ASTM — and evaluate everything else as supporting information.