Vertical & Horizontal Bladder Tank
Foam Storage Devices | Model MXC


The bladder tank together with ratio controllers, form a balanced pressure proportioning system used to mix water and firefighting foam concentrate together to produce an effective extinguishing medium. The bladder tank technology is a dependable and precise mixing method that is widespread in the fixed fire protection market. This method gives a stable water/foam ratio by adjusting automatically to the variable flow rate and pressure conditions that occur during system operation. This feature makes bladder tanks particularly suitable to fit multiple hazard systems, sprinkler systems and any other systems operating under variable, non-predictable flow and pressure conditions. The bladder tank is a carbon steel pressure vessel containing an elastomeric bladder between the water and foam concentrate. The bladder permits water pressure to be transferred to the foam concentrate without the two fluids mixing together.

This technical data is intended for trained experts. It contains basic information needed to use the product described. Legally binding is the product operation and maintenance manual, which must be observed. Technical data can be found on the KCA website at The website may include a more recent edition of this technical data sheet. For further information, please contact KCA or refer to the technical documentation. The contents of this publication are subject to modifications without notice.

Listings and approvals

The bladder tank is FM Approved and/or UL Listed as part of a fire extinguishing system combining designated foam concentrates, model KFP ratio controllers, Model KBP ILBP’s and discharge devices. Approved and listed system components can be found at and

  • FM Approved – Low Expansion Foam Systems (FM5130)
  • UL Listed – Guide GHXV.EX26572 (UL162)
  • Manufactured according to ASME Sec. VIII Div.1 or EN13445
  • CE marked according to the PED Directive 2014/68/EU (Europe Only)
  • Fire Safety Certified for Russian Federation territory CTP (formally GOST)
  • ASME U-1A (“U” Stamp) certification process available on request with additional charge. See data page TD2.3.1.3 for ordering information.

Notice: Other international approval certificates may be available upon request.

Vertical & Horizontal Bladder Tank Foam Storage Devices | Model MXC

Technical data
Construction features

  • Vertical tanks on legs or horizontal tanks on saddles
  • Legs and saddles are provided with ground fixing holes
  • Approved system design pressure of 175 PSI (12.1 bar) or 232 PSI (16.0 bar)
  • 100% pressure tested according to the applied design code
  • Shell and heads in ASTM A516 Gr. 70 or EN10028-3 P275NH/P355NH
  • Lockable corrosion resistant brass tank trim/service ball valves (UL Listed / FM Approved)
  • Inspection flange available on left or right side of horizontal tanks (left as standard)
  • Machine welded circumferential and longitudinal seams for maximum quality and durability
  • Welded lifting lugs to facilitate safe handling operations
  • Earth lug for electrical safety
  • Safety thermal valve on water side of bladder to prevent slow overpressure and relieve thermal fluctuations

Standard materials

Tank shell and heads ASTM A516 Gr. 70 or P275NH to EN10028-3 or P355NH to EN10028-3
Bladder Polyester reinforced hypalon-neoprene polymers
Trim valves Brass
Safety thermal relief valve Brass
Pressure gauges Stainless steel
Level indicator Hydrometer: Stainless steel or Sight tube: PVC
Paint Epoxy zinc rich primer with aliphatic polyurethane finish
Standard colour Flame red RAL3000
Flange material ASTM A105
Flange connection ANSI B16.5 Class 150
  • Bladder equipped with cast rubber caps to ensure water & foam integrity under constant pressure
  • Bladder specifically tested for compatibility with foams shown in FM Approval and UL Listing
  • Oversized to permit concentrate thermal expansion (volume expansion allowance)
  • Tank equipped with inside protection at any opening to ensure no damage to the bladder
  • Internal PVC foam concentrate distribution pipe ensures optimal foam concentrate usage
  • Internal water distribution channel to equalize the water pressure everywhere avoiding damage to the bladder and to drain the tank during service and maintenance
  • Nameplate holder to avoid undetected corrosion on the tank’s shell behind the plate
  • Analog level indicator or classic sight tube (specify at point of order)
  • External epoxy zinc rich primer with aliphatic polyurethane finish tested by FM and UL for corrosive atmosphere (salt fog)


Standard design specifications

Design pressure 175 PSI / 12.1 bar (1.2MPa) or 232 PSI / 16.0 bar (1.6MPa)
Operating temperature range 35°F to 120°F (1.7°C to 49°C)
Capacity See tables in datasheet
Empty weight See tables in datasheet
Proportioning range See ratio controller datasheet
(*) Further temperature limitations come from foam concentrate and water.
See more information in the datasheet.

Scope of delivery

Ensure that all components are complete and in good condition. The bladder tank is supplied in or on a suitable wooden pallet skid or shipping crate in the horizontal position. All bladder tanks have lifting lugs to allow safe maneuverability on site. Tank is supplied empty with pre-installed bladder. Small trim valves and contents level device are supplied pre-assembled to the tank as standard. Safety thermal relief valve supplied as standard according to design code selected. Anchor fixing bolts are not part of our supply scope.


Please contact KCA for further information. The product is available directly from KCA and official distributors only.

Product variants

  • Pre-assembled with ratio controller and water/foam pipe work
  • Twin tank configurations
  • Special coatings for salt-water applications or harsh environmental conditions
  • Nameplate in corrosion resistant material
  • Increased wall thickness for corrosion allowance
  • 233 PSI /16.1 bar (1.6MPa) design pressure rating with UL Listing and FM Approval
  • Other design pressure and seismic ratings
  • Ladders | Work platform | Sunshield
  • Full bladder tank stainless steel construction
  • Heat tracing and/or insulation
  • Bladder tank pre-installed on base frame or containerized to customer requirements
  • Various colors and painting cycles with UL Listing and FM Approval (120-300 microns)
  • Nondestructive examinations
  • Factory acceptance test, notified body or third party inspections
  • Special sea freight and fumigated packaging

Please contact KCA for further details, pricing and availability.
See the datasheet for more information.

Information: Some of the available options may not be covered by the UL listing or FM approval. Please always make
reference to the appropriate approval directory or guides, or contact KCA for further assistance.


Refer to appropriate installation standards (i.e. NFPA, VdS, LPCB, etc.) and / or applicable FM Global Property Loss Prevention Data Sheets such as 4-12, Foam-Water Sprinkler Systems. The KCA installation, operation and maintenance bladder tank manual shall also be referenced.

Notice: When designing a bladder tank into your fire protection system, please give consideration to future maintenance activities. Ensure that adequate clearance above a vertical bladder tank or at the inspection flange end of a horizontal tank is allowed. For further guidance contact KCA.


  1. Foam concentrate is stored inside the bladder. When used in conjunction with a ratio controller it proportions foam concentrate accurately into the water stream.
  2. During system activation, the outer side of the bladder is pressurized by the system water supply which forces foam concentrate to the ratio controller
  3. Simultaneously, as water flows through the venturi area of the ratio controller, a metered pressure drop draws foam concentrate into the system water stream creating a foam solution mixed to the appropriate ratios.
  4. The foam solution flows through the system pipework and out of any open sprinklers, nozzles or other discharge devices.
  5. As the foam concentrate continues to flow from the inside of the bladder, system water enters the bladder tank on the outside of the bladder keeping a balanced pressure system.


For details of warranty, refer to KCA’s current list price schedule or contact KCA directly.

Inspections, tests and maintenance

Warning: Any system maintenance or testing that involves placing a control valve or detection system out of service may eliminate the fire protection capabilities of that system. Prior to proceeding, notify all Authorities Having Jurisdiction. Consideration should be given to employment of a fire patrol in the affected area.

Refer to respective requirements, according to the relevant standards for Inspection, Testing and Maintenance. If applicable, refer to FM Global Property Loss Prevention Datasheet 4-12 for specific test and commissioning criteria. In addition, the “Authority Having Jurisdiction” (AHJ) may have additional maintenance, testing and inspection requirements that must be followed.


At end of use the product described here should be disposed of via the national recycling system. Upon request the manufacturer can take back and properly dispose of the electrical equipment and electronic devices.

Declaration of conformity

If required. Contact KCA for further information.