When people specify an Armco barrier system, attention naturally goes to the beam — its length, its gauge, its finish. The terminal end rarely gets the same scrutiny. That's a problem, because the fishtail terminal end is arguably the most safety-critical component in the entire installation.
What is a fishtail terminal end?
A fishtail terminal end is the shaped steel section that closes off the exposed end of an Armco corrugated beam run. Without it, the raw edge of a steel barrier presents a direct spearing risk to any vehicle that strikes it at an angle — or to any pedestrian who contacts it. The fishtail profile — widened and curled outward at the tip — is designed to deflect impact energy away from the vehicle rather than concentrate it at a point.
It is not a cosmetic finish. It is a functional safety component.
Where fishtail terminal ends are required
Any Armco installation where the end of the beam run is accessible to vehicle or pedestrian traffic requires a terminal end. This includes:
- The start and finish of barrier runs in car parks and loading areas
- Barrier ends adjacent to pedestrian routes
- Any installation where the beam end faces oncoming traffic
- Indoor warehouse runs where forklift or vehicle traffic passes end-on
If the terminal is fixed to a wall or structure on both ends and fully enclosed, a terminal end may not be required. In all other cases, it should be treated as mandatory.
Key specifications
UK Armco installations typically use W-beam corrugated steel (the standard highway profile). Terminal ends must match the beam profile and gauge to maintain structural continuity. Standard specifications:
- Material: hot-rolled steel, typically 3mm minimum gauge
- Finish: hot-dip galvanised to BS EN ISO 1461 or powder-coated safety yellow
- Profile: must match the parent beam (W-beam or open box beam)
- Fixing: bolted through the beam with compliant coach bolts or barrier bolts — never welded in the field
The flared width of the fishtail profile is typically 300–400mm at the widest point. This spread distributes any impact load across a broader surface, reducing penetration risk.
Common installation errors
The most frequent problem seen on site is simply the omission of a terminal end — either because it wasn't included in the original specification or because it was treated as optional. The second most common issue is mismatched profiles: using a terminal end designed for standard W-beam on an open box beam installation, or vice versa. The profiles are not interchangeable.
A third issue is incorrect orientation. The fishtail flare should face away from the direction of approaching traffic — this ensures that a vehicle striking the end is pushed away from the barrier, not funnelled into it. The terminal end can be flipped to suit your installation direction, so orientation is simply a matter of positioning it correctly on site.
Compliance context
For highway installations in the UK, terminal end specifications are governed by the relevant Design Manual for Roads and Bridges (DMRB) standards. For private and industrial sites, there is no single mandatory standard, but best practice follows the same engineering logic: any barrier run accessible to vehicle impact should be terminated in a manner that eliminates spearing risk.
For industrial estate, warehouse, and car park installations — the environments most BarrierBase customers operate in — the fishtail terminal end should be treated as a standard line item, not an optional extra.
Ordering the right component
When specifying a terminal end, confirm: beam profile, gauge, and finish. Most runs need one terminal end per exposed beam end. If you're unsure which specification suits your site, send us your site drawing or a photo of the installation and we'll confirm the right spec.