NAFFCO NDR 097 Oblique Landing Valve, Threaded Inlet (BS 5041)

Overview

The NAFFCO NDR 097 is a BS 5041 Part 1 oblique landing valve with a male threaded inlet, nominal size DN 2½ inch, for wet riser systems that remain permanently charged with water from a pressurised supply. Where the flanged NDR 098 bolts to a flanged branch, the NAFFCO NDR 097 screws directly onto a threaded riser outlet, which suits smaller buildings, retrofit work and installations where threaded branches are already in place. Its delivery hose connection and blank cap comply with BS 336:2010, it is classified as a low pressure valve for nominal inlet pressures up to 15 bar, and NAFFCO lists it as BSI Kitemark approved.

Seven Star LLC supplies the NAFFCO NDR 097 to fire fighting contractors, facility management companies and building owners in Oman, with engineering support in Muscat. Clients looking for a supplier of landing valves in Muscat for threaded wet riser outlets can use the NAFFCO NDR 097 datasheet for consultant and civil defence submittals.

Operating Principle

On each floor of a wet riser installation, the landing valve is the controlled outlet where the fire service connects its hose. With the riser constantly pressurised, opening the handwheel of the NAFFCO NDR 097 lifts the renewable disc off its seat, and water passes through the body and the downward-angled oblique outlet into the hose. The published water flow rate is 8.5 litres per second at 4 bar outlet pressure, the same figure NAFFCO gives for the flanged versions.

When the handwheel is closed, the disc facing is pressed onto the seat and holds back the riser pressure. As general background, the outlet uses a BS 336 female instantaneous connection, which allows a hose coupling to be pushed on and locked in a single movement, a feature valued by fire crews working under time pressure. The blank cap protects the outlet between uses and is retained by a chain so it is not lost.

Engineering Design of the NAFFCO NDR 097

NAFFCO builds the body, bonnet, female instantaneous outlet, blank cap and gland of the NAFFCO NDR 097 from copper alloy to EN 1982, with a copper alloy stem to BS EN 12164. The handwheel is grey cast iron to BS EN 1561 and is painted black, while the body is finished in red. Sealing components, namely the renewable disc facing, washer and gland seal, are rubber to BS 1154, and the bonnet seal is PTFE.

The inlet is a male thread at the base of a hexagonal body section, as shown on the datasheet drawing, allowing the valve to be tightened onto the riser branch with a spanner. Like the flanged models, the NDR 097 allows the gland seal to be replaced while under pressure with the valve fully closed, and the disc facing rubber is a replaceable type. A strap with padlock, made from leather 12 mm wide and 2 mm thick with a non-ferrous lock, secures the handwheel against unauthorised operation.

Key Features

Features of the NAFFCO NDR 097 listed on the NAFFCO datasheet are summarised here.

• Oblique pattern with a male threaded inlet, nominal size DN 2½ inch.
• Built to BS 5041 Part 1, the British standard for wet riser landing valves.
• Its instantaneous hose outlet and chained cap follow BS 336:2010.
• The NAFFCO NDR 097 is stated as BSI Kitemark approved.
• Body and blank cap are copper alloy to EN 1982; handwheel is grey cast iron to BS EN 1561.
• With the valve shut, its gland packing seal can be renewed while the riser stays pressurised.
• A renewable rubber facing on the disc restores tightness after wear.
• A strap and padlock prevent unauthorised use; the handwheel is black and the body is red.

Industrial Applications

Threaded landing valves such as the NAFFCO NDR 097 are common on wet riser outlets in mid-rise apartment blocks, schools, clinics, labour accommodation, villas compounds with shared fire mains, and small commercial buildings, as well as on replacement work where the existing riser branches are threaded. Fire protection maintenance contractors in Oman often stock threaded valves for like-for-like replacement during annual inspections, because a damaged or leaking landing valve must be replaced quickly to keep the building compliant.

Seven Star LLC supplies the NAFFCO NDR 097 for new projects and maintenance contracts in Muscat, Sohar, Nizwa, Salalah and across Oman. It is typically used within a fire protection system that also includes grooved pipe joints such as the Victaulic Style 107N QuickVic coupling, clean agent protection for electrical rooms such as the Kidde FM-200 200 lb cylinder, and alarm panels such as the Gent Vigilon Compact Plus fire alarm panel.

Technical Specifications

NAFFCO NDR 097 data below comes from the NAFFCO technical datasheet for the oblique male threaded inlet landing valve.

Selection and Installation Notes

This section gives general guidance and is not issued by NAFFCO. Before ordering, confirm the thread form and size of the existing riser branch so that the male inlet of the valve matches it; an incorrect thread is one of the most frequent causes of site delays on replacement work. Apply a thread sealant or tape suitable for fire water service and tighten the valve so that the outlet finishes facing the correct direction for hose run-out, rather than over-tightening to reach the required angle.

After installation, the system should be pressure tested and the valve checked for leaks at the gland and inlet thread, with the strap and padlock fitted and the blank cap in place. Inspection frequency and acceptance tests are set by the approved design and the local civil defence requirements.

How to Order

For a quotation on the NAFFCO NDR 097, send Seven Star LLC the quantity, inlet thread details and project or maintenance requirement. Our Muscat office can confirm availability and lead time, provide the NAFFCO technical datasheet available for download on this page, and support fire protection work across Oman and the GCC.