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Brand: Viking
Viking Model VLF In-Line Balanced Pressure Foam Proportioner
Description
Accurate foam proportioning at remote risers
The Viking Model VLF is an in-line balanced pressure (ILBP) proportioner. It balances the higher foam concentrate pressure against the lower system water pressure on pilot pressure regulating systems and foam pump proportioning systems. Viking points out that it is particularly useful for accurate proportioning at multiple riser locations that sit remote from the central foam concentrate tank. Different ILBP sizes can share the same concentrate supply, and each automatically adjusts to give accurate proportioning across its tested pressure and flow range.
The data sheet is written for trained experts, and the proportioner is only one part of a foam system that also needs the correct concentrate, bladder tanks and discharge devices.
Technical specifications
| Parameter | Specification |
|---|---|
| Manufacturer / model | Viking, Model VLF in-line balanced pressure proportioner |
| Sizes | 3 in (DN80), 4 in (DN100), 6 in (DN150), 8 in (DN200) |
| Construction | Brass (cast brass UNS C84400) or nickel aluminium bronze (UNS C95800), stainless steel fittings |
| Orifice | UNS-C36000 (brass version); C36000, C46400 or C95800 (nickel aluminium bronze) |
| Design pressure / maximum static | 250 psi (17.2 bar) |
| Operating inlet pressure | 30 psi (2.1 bar) minimum to 150 psi (10.3 bar) maximum |
| Foam concentrate inlet pressure | At least 15 psi above water inlet pressure; maximum 50 psi above at the concentrate controller |
| Design temperature range | 14 °F to 120 °F (-10 °C to 49 °C) |
| Operating temperature range | 35 °F to 120 °F (1.7 °C to 49 °C); riser area kept at or above 40 °F (4.4 °C) |
| Installation / media | Horizontal or vertical; fresh or salt water; flow direction marked on body |
| Printed approvals | FM Approved low expansion foam systems (FM5130); UL Listed guide GHXV.EX5002 (UL 162) |
Approvals apply to the proportioner as part of a system with designated foam concentrates, bladder tanks and discharge devices, so check the FM and UL listings for the exact combination. Not all configurations are available, including those marked SFFF compatible.
Selecting the size and version
Different part numbers cover the connection, the orifice, the foam type and the proportioning percentage, and the data sheet ordering table gives minimum and maximum flow for FM and UL. Pick the size from the flow demand of the riser, then choose between brass and nickel aluminium bronze depending on corrosion exposure, for example salt water or marine duty.
An identification tag plate is fitted, and the data sheet adds guidance on installation, commissioning and inspection with reference to FM Global Property Loss Prevention Data Sheet 4-12.
Viking lists the VLF as suitable for Fomtec LS xMax 3% foam concentrate, in nickel aluminium bronze or brass, and offers a version pre-assembled with a bladder tank and the water and foam pipework. The proportioner assembly includes a ratio controller, nozzle, orifice plate, pressure gauge, mounting plate, spool valve, side outlet valves and sensing line assemblies, and the data sheet lists replacement part numbers for the gauge, plugs, sensing lines and swing check valve.
Related Viking foam product
| Model | Description |
|---|---|
| Model VLF ILBP proportioner | This page: balanced pressure, 3 to 8 in |
| Model VNR wide-range proportioner | Wafer type for 3 percent concentrates, 6 and 8 in |
Browse additional Fire Fighting equipment.
Confirm before ordering
Confirm the foam concentrate type and percentage, the pump or pilot pressure control arrangement, flow range per riser, material and the approval listing required. Foam systems are specified and designed as a package, so the proportioner must be matched to the system design. Send the system data and part number for a quotation.
Datasheets & Documents
- Datasheet Viking Model VLF in-line balanced pressure proportioner technical data, Form F_102721 Rev 04 Download
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About brand
Viking is an American manufacturer of fire sprinklers, valves and special hazard fire protection systems, based in Michigan. The business grew from the work of Emil Tyden, a Swedish immigrant who made railroad car seals in Hastings, Michigan, and turned to sprinklers after buying the struggling Viking Corporation. By the late 1980s Viking had left contracting and design work to concentrate on manufacturing and distribution.
Seven Star LLC is an independent supplier in Muscat. We list selected Viking sprinklers, valves and foam equipment with the manufacturer technical data, for fire protection contractors in Oman and the GCC.
Viking company profile
| Origin | Hastings, Michigan, USA, where Emil Tyden began making sprinklers and valves |
|---|---|
| Headquarters | Michigan, USA (Viking Group) |
| Business model | Manufacturing and distribution through independent sprinkler contractors |
| Special hazards | Includes the Minimax Fire Products range, sold under the Viking name |
| Product families | ESFR pendent sprinklers such as VK500, VK503, VK506 and VK510 for storage protection, standard and quick-response sprinklers, deluge and preaction valves, dry pipe and alarm check valves, foam and special hazard systems |
Milestones
- 1880s: Emil Tyden starts out making railroad car seals.
- Early years: Tyden buys Viking Corporation and starts making sprinklers and valves in Hastings.
- Late 1980s: Viking leaves contracting to focus on manufacturing and distribution.
Viking product series
Sprinklers on this site are ESFR (early suppression fast response) pendent sprinklers for storage: the VK500 K14, VK503 K16.8, VK506 K22.4, VK510 K25.2 and VK514 K28 for storage up to 50 ft, and the VK512 K25.2 dry pendent version for freezers.
Valves include the Model F-1 and Model VXR dry pipe valves, the Model J-1 alarm check valve and the Model EA-1 electronic accelerator for dry systems. Foam products include the Model VLF in-line balanced pressure proportioner and the Model VNR wide-range proportioner in 6 and 8 inch sizes.
Where Viking equipment is used
Warehouses and distribution centres, cold stores, factories, car parks, hangars and fuel and chemical storage, in sprinkler, dry pipe and foam-water systems designed to NFPA standards and local civil defence rules.
Viking products we list
Ordering Viking products: what we need
Send the Viking part number or model, the size, finish and temperature rating for sprinklers, the size, pressure rating and trim for valves, and the approvals (UL, FM) the project requires, together with the quantity and delivery location.
Facts checked against Viking Group's own history pages (vikinggroupinc.com), October 2026.
Browse Viking products by category: Fire Fighting.
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Frequently Asked Questions
What does the Viking VLF proportioner do?
It balances foam concentrate pressure to system water pressure so foam is proportioned accurately across its flow range.
Which sizes does the VLF come in?
3 in (DN80), 4 in (DN100), 6 in (DN150) and 8 in (DN200).
What materials are offered for the VLF?
Brass or nickel aluminium bronze bodies, with stainless steel fittings.
How much higher must the foam inlet pressure be?
At least 15 psi above the water inlet pressure, and at most 50 psi above at the concentrate controller.
Can the VLF be used with salt water?
Yes. Viking states it is for use with fresh or salt water.
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