Anti-ligature Ventilation Plenum

Safe, hygienic air distribution for secure mental health environments designed and built with the practical demands of NHS specification in mind.

Anti-ligature Ventilation Plenum draws on Contour Heating’s years of working within mental health. It is designed specifically for these environments: connecting standard circular ductwork to IP3X-rated anti-ligature grilles, with a construction specification that addresses safety, hygiene, and long-term maintainability from the outset.

Designed for HBN 03-01 Environments

Getting ventilation right in a secure mental health ward is more complex than it looks. Every element of the built environment comes under scrutiny — from CQC inspections to clinical sign-off and infection prevention review. The Anti-ligature Ventilation Plenum from Contour Heating is designed specifically for these environments: connecting standard circular ductwork to IP3X-rated anti-ligature grilles, with a construction specification that addresses safety, hygiene, and long-term maintainability from the outset.

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Ward Uses

The Anti-ligature Ventilation Plenum is specified for secure mental health estates where standard ventilation grilles present unacceptable risk. Typical applications include:

• Acute adult inpatient wards requiring anti-ligature specification

• PICU and high-dependency mental health settings

• CAMHS inpatient units

• Rehabilitation and step-down wards

• Seclusion, low-stimulus, and en-suite bathroom areas

• Any space where standard ventilation grilles present a ligature or anti-tamper risk

The plenum is suitable for both new-build hospital construction and phased refurbishment programmes in occupied clinical environments.

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IP3X-rated anti-ligature punched grille; 2mm holes at 4mm centres.

1.5mm Zintec steel (full frame); Magnelis steel available for wet areas.

BioCote® antimicrobial agent as standard.

Pin Torx button head anti-ligature fixings; threaded inserts for maintenance access; all fixings internal.

Top-entry circular spigot; 125mm, 160mm, 200mm nominal sizes; compatible with standard round flexible and rigid ductwork.

Typically 8–10 Pa at nominal flow rates; extract higher — factor into system design.

Technical Data

IP3X anti-ligature grille

The punched steel grille uses 2mm holes at 4mm centres in a triangular pitch. This restricts the passage of objects, reduces ligature opportunities, and maintains the airflow performance the system needs. It sits flush with the ceiling once installed, with no projecting edges.

1.5mm Zintec steel

The plenum body is formed from 1.5mm Zintec steel — a specification suited to high-use clinical settings where impact and wear are everyday considerations. Magnelis steel is available for wet-room and en-suite environments where additional corrosion resistance is needed.

Low pressure drop

Supply air testing shows a pressure drop typically in the range of 8–10 Pa at nominal flow rates — low enough to avoid adverse system effects. Extract pressure drop is higher due to grille restriction and should be factored into system design at specification stage.

BioCote® antimicrobial protection

Powder coated inside and out as standard on RAL 9003 white models. BioCote® antimicrobial agent is incorporated into the finish, supporting hygiene standards and infection prevention requirements in clinical environments.

Anti-ligature fixings

Pin Torx button head fixings create a flush, secure closure. All fixing points are located internally, protecting against unauthorised access, removal, or manipulation. Threaded inserts support repeated removal and refitting for maintenance without wear to the fixing points.

Flush ceiling installation

The grille sits flush with the ceiling surface once installed, with the plenum body attached internally to the ductwork. There are no projecting frames, exposed fixings, or surface-mounted elements that could present a risk or accumulate contamination.

Supply and extract

The plenum supports both supply and extract applications. For supply, air enters via the top-entry spigot, diffuses through the plenum chamber, and passes through the grille into the room. For extract, the airflow direction is reversed. This allows a consistent product specification across ventilation systems.

Richard Holland National Sales Manager

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Richard Holland National Sales Manager

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Robert Bennett Project Surveyor

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Laura Oliver Customer Service Manager

How Can We Help You?

Grille size	H × W × D	Spigot
200 × 200 mm	250 × 250 × 250 mm	Ø125 mm
300 × 300 mm	350 × 350 × 300 mm	Ø160 mm
450 × 450 mm	520 × 520 × 400 mm	Ø200 mm

Anti-ligature Ventilation Plenum

Designed for HBN 03-01 Environments

Ward Uses

Key features

Technical specification