Description
FEATURES
• UL Listed & FM Approved
• Heavy duty welded construction with choice of
Carbon Steel or Stainless Steel material
• Frangible Glass Vapour Seal
• Controlled Air Flow proportional to liquid flow for
optimum foam quality and rupture of vapour
seal in narrow pressure tolerances for
increased reliability
• Field replaceable orifice plate fitted with Foam
Chamber
APPLICATION
Foam Chamber is used in one of the most common applications to protect vertical fixed roof (cone) liquid storage tanks, with or without internal floating roof with the low expansion foam system. The application of foam is on the basis that the risk comprises the total surface area of the fuel. The foam system design guidelines generally used are in accordance with NFPA-11 standard.
Foam Chambers are defined by NFPA-11 as Type II discharge outlets for delivering foam to the surface of a flammable liquid. Foam Chambers are widely used with the Balance Pressure Foam Proportioning System, Bladder Tank Proportioner or Foam Tender.
MODELS FCA 50
FCA 65
FCA 80
FCA 100
FCA 150
FCA-S 50
FCA-S 65
FCA-S 80
FCA-S 100
FCA-S 150
INLET SIZE 50, 65, 80,100 NB & 150 NB
WORKING Minimum 2.8 kg/sq.cm (40 psi)
PRESSURE Maximum 7 kg/sq.cm (100 psi)
FLANGE ANSI B16.5 Class 150#SORF
CONNECTION
WEIGHT 50 NB – 29.9 kg
(Approx.) 65 NB – 34.5 kg
80 NB – 49.5 kg
100 NB – 72.0 kg
150 NB – 110.0 kg
VAPOUR SEAL 0.7 to 1.75 kg/sq.cm
RUPTURE (10 psi to 25 psi)
PRESSURE Running water/ water foam
solution pressure at inlet of
Foam Chamber
MAXIMUM 0.07 kg/sq.cm (1.0 psi)
PERMISSIBLE BACK
PRESSURE ON
VAPOUR SEAL
VAPOUR SEAL Glass standard supply,
Graphite optional only with
FM Approvals
DEFLECTOR Solid or Split Deflector
FINISH Red RAL 3001 standard supply
Other shades optional
APPROVAL UL Listed & FM Approved
ORDERING a) Model & Size
INFORMATION b) Flow & Pressure at inlet
of each Foam Chamber
c) Inlet, outlet flange
specification
d) Type of Deflector
e) Type of Foam concentrate
used
f) Tank number / Tag number
Carbon Steel
construction
Stainless Steel
construction
JULY, 2022 PAGE 2 OF 8 HD 254
HD FIRE PROTECT
PVT. LTD.
SPECIFICATION
Foam Chamber is an air aspirating foam discharge device, covering wide range of flow from 75 to 3300 litres per minute at 2.8 to 7 kg/sq.cm inlet pressure. The Foam Chamber contains a vapour seal to prevent the entry of fuel vapour into the foam chamber and the
foam solution pipe. Each foam chamber is supplied with an orifice plate, designed for the required flow and inlet pressure. The orifice is field replaceable in the event of change in design parameters. Foam is produced by introducing air into the foam solution stream. The inlet of foam chamber is designed to create venturi jet which draws air into the foam solution stream. Air is drawn into the foam solution
through the holes located on the foam chamber covered with stainless steel screen to exclude nesting birds and insects. The aerated foam is directed into the deflector for gentle application of the expanded foam. The deflectors are available in different models.
Removal of cover plate from the top of the chamber allows the system to be tested and a sample of the expanded foam can be collected without removing the vapour seal or disconnecting the foam chamber from the tank. Frangible glass bursting disc/graphite (vapour seal) can be replaced easily. The vapour seal is designed to rupture within 0.7 to 1.75 kg/sq.cm (10 to 25 psi) pressure at inlet flange of Foam Chamber, as required by NFPA, UL and FM standard. The vapour seal will withstand maximum back pressure of 0.07 kg/sq.cm (1.0 psi)
or equal to 686 mm of water column as specified by API for welded storage tank. If the requirement exceeds 0.07 kg/sq.cm (1.0 psi) as in case of nitrogen blanketing system, then this equipment may not be suitable. The vapour seal is frangible glass. Vapour seal is supplied with holder and for spares it can be with or without holder. The ‘O’ ring used for seal are Nitrile Rubber and optional Viton is recomended for polar solvent.
SYSTEM DESIGN REQUIREMENT
The NFPA-11, a standard for low expansion foam, provides the essential requirements of an appropriate designed foam pouring system, these are identified and outlined as below: The Foam Deflector is used with the Foam Chamber. The aerated foam from the Foam Chamber is directed in to the deflector for the gentle application of the expanded foam. The deflector reduces the expanded foam velocity and allows the foam to slide down the tank wall. (a) Number of Foam Chamber: The number of foam chambers required is determined by tank diameter. Where two or more foam chambers are required, they shall be spaced equally around the tank periphery and
each Foam Chamber shall be sized to deliver foam at an approximately same rate. Pleaserefer graph to select unit that will provide
required minimum foam solution application rate at the available operating pressure of the Foam Chamber.
For minimum number of Foam Chamber requirement, kindly follow the recommendations as per NFPA/OISD or as per the governmental
codes or ordinances wherever applicable. (b) Minimum Foam Solution Application Rate: The minimum foam solution application rate is the rate at which the water and foam concentrate in correctly proportioned ratio should be delivered to the surface of a storage tank under protection to control and extinguish the fire. For minimum application rate requirement, follow the recommendations as per NFPA/OISD or governmental codes or ordinances whereever wherever applicable. TESTING & MAINTENANCE Carefully unpack Foam Chamber. While unpacking and installation it is to be handled with care and shocks to be avoided. Check visually for any damages. While installing ensure that Foam Chamber is not under stress due to any misalignments in installation or variations of system piping. Ensure that the strainer assembly is clear from any blockages or damages. If strainer assembly is either blocked or damaged, it will
adversely affect the performance of the equipment. Qualified and trained person must commission the system. After few initial successful tests, an authorized person must be trained to perform inspection and testing of the system. It is recommended to carry out physical inspection of the system regularly. The system must be fully tested at least once in a year or in accordance with
applicable NFPA/OISD standards or in accordance with authority having local jurisdiction. Do not turn off the system or any valve to make
repair or test the system, without placing a roving Fire Patrol in the area covered by the system. The Patrol should continue until the system is put back in service. Also inform the local security guard and control alarm station, so as to avoid false alarm. Each system is to be flushed properly. The vapour seal must be replaced if the system has been operated. JULY, 2022 PAGE 3 OF 8 HD 254
HD FIRE PROTECT PVT. LTD. Normal testing of the chamber can be carried out by removing the cover plate from the top of the chamber.
This allows the system to draw a sample of the expanded foam without removing the vapour seal or disconnecting the Foam Chamber from the tank. The air screen is to be inspected periodically for the obstruction of air inlet holes. If any obstruction is
noticed, remove the same and flush if necessary. It is recommended to have regular maintenance programme to inspect the Vapour Seal Chamber discharge area and deflector for possible deposit or obstruction. The owner is responsible for the testing, inspection &
maintenance of the Foam Chamber. CAUTION Do not install Foam chambers on pressured storage tanks (Inert gas blanketed tanks) and storage tanks containing products, which may attack the foam chamber standard construction material. Maximum permissible back pressure on vapour seal is 0.07 kg/sq.cm (1.0 psi)
NOTE:
1. A PROVISION IS TO BE MADE FOR PRESSURE GAUGE MOUNTING AT INLET OF FOAM CHAMBER, WHICH MAY BE PLUGGED AFTER
SUCCESSFUL COMMISSIONING OF THE SYSTEM. THIS PROVISION WILL HELP TO ANALYSE THE SYSTEM WHILE COMMISSIONING.
2. FM APPROVAL AND UL LISTING OF EQUIPMENT ARE VALID ONLY WHEN USED WITH HD FOAM CONCENTRATE IN A MANNER
AS LISTED AND AS PER FM APPROVAL DATA. 3. FM APPROVAL IS VALID ONLY WHEN TOTAL SYSTEM IS HAVING FM APPROVED PRODUCT. 4. REFER TO THE INDIVIDUAL FOAM UL LISTING AND FM APPROVAL, FOR LIMITATION WITH EACH FOAM CONCENTRATE AND FOAM CHAMBER.