Tempest LeaderMix Foam Proportioner: Autonomous Class A and B Foam Dosing for 50 to 500 GPM Operations

When a flammable liquid fire breaks out at a tank farm or petrochemical facility, the foam proportioner is not the place to discover an electronics failure. Voltage fluctuations, blown fuses, dead batteries, and solenoid faults have all ended foam attacks before they started. The Tempest LeaderMix was engineered around one core constraint: deliver accurate foam concentrate dosing across the entire operational flow range with zero reliance on electrical power of any kind. That single design decision produces a proportioner that keeps working when every other electronic system on the apparatus has failed.

What is the Tempest LeaderMix foam proportioner and how does it work?

The Tempest LeaderMix is an autonomous, automatic foam proportioner manufactured by Tempest of Fresno, California. It operates entirely on hydraulic flow dynamics, with no electronics, no external power supply, and no batteries required. When water passes through the unit, differential pressure mechanics draw foam concentrate into the water stream at a precise ratio, automatically adjusting as the flow rate changes.

This fully mechanical proportioning principle means the LeaderMix remains functional in every electrical failure scenario an apparatus can encounter: alternator failure, blown fuses, water damage to control electronics, or power interruption during a transition from one water source to another. The unit handles a flow range of 50 to 275 GPM in standard configurations and 80 to 500 GPM in the high-flow variant (item i40.90.218 and i40.90.208), covering the full operational demand of most structural, wildland interface, and industrial suppression operations without swapping equipment in the field.

What is the difference between Class A and Class B foam, and which does the LeaderMix support?

Class A foam concentrates are formulated for ordinary combustibles: wood, brush, paper, and structural building materials. They reduce the surface tension of water so it penetrates deep into burning material and clings to exposed surfaces as a fire-retardant barrier. Class B foam concentrates are designed for flammable liquid fires, including petroleum products and petrochemical storage, where a vapor-suppressing blanket must form across the fuel surface to cut off oxygen.

The LeaderMix is compatible with all types of foam concentrates in both Class A and Class B categories. This dual compatibility is built into the proportioner’s hydraulic design rather than achieved through field-swappable components. A single unit can serve a wildland engine running Class A on a vegetation fire and then be redeployed to a flammable liquids incident running Class B without modification. For environments where regulatory compliance requires the elimination of PFAS compounds, Tempest specifically recommends BIO-EX Fluorine-Free Foam through the Tempest official product line, a concentrate that is compatible with the LeaderMix’s proportioning mechanism and meets current fluorine-free requirements for sensitive environments.

Why does autonomous hydraulic proportioning outperform electronic proportioners in field reliability?

Electronic foam proportioning systems depend on a functioning power supply, working sensors, calibrated control modules, and operational solenoids. Any one of those components failing during a fire attack interrupts foam delivery and forces crews to revert to manual workarounds. Hydraulic proportioners eliminate that entire failure chain by replacing electronics with pressure differential mechanics that activate the moment water begins to flow.

The LeaderMix’s mechanical design means there is no calibration drift from sensor aging, no firmware update required, and no sensitivity to electrical interference from generators or pumping equipment operating nearby. The proportioner instantly adapts to flow rate variations without manual adjustment, which is particularly critical when operators cycle between attack lines, open or close additional discharges, or transition from draft to pressurized water supply. Because the hydraulic mechanism responds to actual flow physics rather than a programmed control loop, the response to flow change is immediate rather than lagged by sensor polling intervals or solenoid actuation delays.

What flow rates and connection sizes does the LeaderMix support?

The LeaderMix is available in two flow tiers. Standard models cover 50 to 275 GPM with 2.5-inch NH female and male connections, which align with the standard hose thread coupling found on most North American fire apparatus and portable pump systems. High-flow models extend the range to 80 to 500 GPM with 4-inch NPT female-to-female connections, sized for the larger supply lines and manifold inlets found on industrial fire suppression systems and large-diameter handline operations at petrochemical facilities and tank farms.

The eight-model product lineup covers every common deployment configuration. Fixed unit installations use items i40.90.110 and i40.90.112 (53 to 264 GPM, with or without control panel). Portable operations use items i40.90.118 and i40.90.120 (2.5-inch NH, 50 to 275 GPM). Vehicle-mounted systems with integrated control panels are available as items i40.90.119 and i40.90.121. The high-flow 4-inch NPT models (i40.90.218 portable, i40.90.208 vehicle-mounted) are specifically designated for the 80 to 500 GPM range needed in large industrial operations. Stocking the appropriate model eliminates the need to carry multiple proportioners of different sizes on a single apparatus or in a foam trailer.

When should you choose the LeaderMix over a metered or inline eductor-type proportioner?

Inline eductors are pressure-sensitive: they require a specific inlet pressure and specific back-pressure at the nozzle to maintain the rated mixing ratio, and they perform correctly only at or near their rated flow, not across a wide range. Metered proportioners with electronic controls perform well in stable, planned installations but add failure modes and require power infrastructure. The LeaderMix addresses the specific scenario where neither constraint is acceptable: variable flow operations, field-portable deployments, or any setting where electrical reliability cannot be guaranteed.

The single-unit design that covers the full 50 to 500 GPM range without operator intervention is particularly valuable during mutual aid operations, where incoming apparatus may be running at different pressures and flow rates than the host department’s equipment. Rather than carrying separate proportioners sized for 100 GPM, 250 GPM, and 500 GPM scenarios, a single LeaderMix handles the full range. This reduces apparatus weight, eliminates field equipment swaps during active suppression, and removes the human error associated with manually switching between sized eductors when tactics change mid-incident.

How does PFAS-free foam compatibility affect proportioner selection for industrial and municipal operators?

PFAS (per- and polyfluoroalkyl substances) contamination from aqueous film-forming foam (AFFF) has prompted regulatory restrictions and outright bans at airports, military installations, and industrial facilities across multiple U.S. states and internationally. Operators at petrochemical facilities and tank farms are under increasing pressure to transition from AFFF-based Class B concentrates to fluorine-free alternatives before regulatory deadlines apply to their facility class.

The LeaderMix is compatible with fluorine-free foam concentrates, including Tempest’s recommended BIO-EX product. This matters for proportioner selection because not all mechanical proportioners have been validated with the different viscosity and surface tension characteristics of fluorine-free concentrates compared to legacy AFFF. Specifying a proportioner that is confirmed compatible with PFAS-free formulations protects the capital investment when foam concentrate inventory transitions from AFFF to fluorine-free products. Facilities planning that transition can install the LeaderMix now and change concentrate without replacing hardware. The U.S. EPA PFAS regulatory framework continues to evolve, making concentrate compatibility a forward-looking specification requirement, not a future consideration.

What configurations and control panel options are available for monitored operations?

The LeaderMix is offered in fixed, portable, and vehicle-mounted configurations. Fixed units (i40.90.110) are suited for permanent installation at pump houses, foam skids, or suppression system pump rooms where the proportioner is integrated into a pre-piped system. Portable units (i40.90.118) use 2.5-inch NH connections for rapid deployment directly from hose packs or foam carts. Vehicle-mounted units with control panels (i40.90.119, i40.90.121, i40.90.219, i40.90.208) allow incident commanders and pump operators to monitor foam system performance during complex multi-line operations.

The control panel option does not change the autonomous hydraulic operation of the proportioner itself. The panel adds monitoring and management visibility for operations where multiple foam lines are active simultaneously and a supervisor needs situational awareness of concentrate consumption and system status. This is common in large industrial facility responses where foam application is coordinated across multiple suppression zones. The control panel variants retain the same no-external-power-required mechanical core, so the monitoring functionality is additive, not a dependency for basic operation.

Where is the Tempest LeaderMix used? Applications across fire and industrial suppression

The LeaderMix is deployed across municipal fire apparatus, industrial fire brigades, wildland engine programs, and fixed suppression infrastructure in petrochemical and energy sector facilities. Structural engine companies running Class A foam for overhaul and interior suppression use the 50 to 275 GPM standard models. Aircraft rescue and firefighting (ARFF) vehicles operating at industrial airfields use the high-flow 80 to 500 GPM models for rapid Class B application across fuel spill areas. Tank farm and petrochemical plant fire suppression systems use fixed and vehicle-mounted configurations to deliver the high-volume Class B foam application rates that large hydrocarbon storage fires require.

For fire professionals sourcing foam proportioning equipment alongside broader apparatus hardware and fire suppression components, the following resources cover complementary product categories: the foam equipment product category at PE Energy covers system components for structural and industrial foam operations. Teams outfitting complete suppression systems can also review fire suppression equipment at PE Energy for integrated system components. For the full Tempest product lineup including the LeaderMix and compatible accessories, see the Tempest brand page at PE Energy. Industrial operators setting up complete foam systems for tank farm or petrochemical applications can also find relevant hardware in the industrial fire protection section at PE Energy.

When is the LeaderMix the right call, and when is it not?

The LeaderMix is the correct specification when operational reliability across a wide flow range matters more than digital monitoring integration, when electrical failure cannot be ruled out, or when a single unit needs to cover both Class A and Class B foam operations without equipment changes. It is the appropriate choice for vehicle-mounted systems at petrochemical and tank farm facilities, portable wildland engine kits, and any fixed installation where PFAS-free concentrate compatibility is a current or anticipated requirement.

It is not the right tool when a facility requires full SCADA integration or digital flow telemetry reported to a central control system, since the LeaderMix’s autonomous mechanical design does not output electronic data signals. Operations that are permanently fixed at a single precise flow rate with stable inlet conditions and no flow variability may find that a simpler fixed-ratio eductor sized to that single flow is sufficient. For everyone else operating in the real-world conditions of variable flow, variable supply pressure, mixed foam types, and uncertain electrical reliability, the LeaderMix’s design constraints are features rather than limitations.

Tempest Fire

LeaderMix Foam Proportioner

Autonomous & Automatic | 50–500 GPM | Class A & B Foam | No Power Required

Overview

The Tempest LeaderMix is an autonomous, automatic foam proportioner that requires no electronics and no external power supply. It allows precise dosing of all types of foam concentrates (Class A and B) between 50 and 500 GPM, instantly adapting to flow rate variations without manual adjustment.

Available in portable and vehicle-mounted configurations, the LeaderMix is designed as one inductor for all flows — a single system that handles the full flow range without swapping equipment. Available with control panels for monitoring and management in complex operations.

Models & Ordering Information

Manufacturer: Tempest — 4708 N. Blythe Avenue, Fresno, California 93722 USA — tempest.us.com