The 2006 edition of IS 4989 outlines the criteria for foam concentrates intended for producing mechanical foam used in firefighting. It specifies the chemical, physical, and fire-resistance properties for low-expansion foam concentrates with concentrate ratios of 1%, 3%, and 6%, including protein-based, film-forming fluoro-protein, and aqueous film-forming foams. The standard also provides detailed testing protocols for foam generation, stability, expansion, drainage, and fire suppression effectiveness, serving manufacturers, quality assurance teams, and fire protection engineers.
Overview
The 2006 edition of IS 4989 outlines the criteria for foam concentrates intended for producing mechanical foam used in firefighting. It specifies the chemical, physical, and fire-resistance properties for low-expansion foam concentrates with concentrate ratios of 1%, 3%, and 6%, including protein-based, film-forming fluoro-protein, and aqueous film-forming foams. The standard also provides detailed testing protocols for foam generation, stability, expansion, drainage, and fire suppression effectiveness, serving manufacturers, quality assurance teams, and fire protection engineers.
Audience
Contents
Structure
IS 4989 defines foam concentrates suitable exclusively for top application on fires, excluding specialized base injection systems for storage tanks. It references multiple Indian Standards for related materials and specifies key physical and chemical parameters such as pH, specific gravity, miscibility, pour point, sludge content, and spreading coefficient. The centrifuge speed formula and film formation test setup dimensions are also detailed.
The standard categorizes foam concentrates into three types based on dilution ratios with water: Type 1 (1% concentrate), Type 3 (3% concentrate), and Type 6 (6% concentrate), each tailored for specific expansion properties. It outlines essential characteristics and preparation methods for foam solutions, emphasizing the use of distilled water with a minimum surface tension requirement.
This section lists detailed physical and chemical criteria for foam concentrates, including pH ranges, specific gravity, miscibility, pour point, sludge content limits, and spreading coefficient minimums. It also describes centrifuge parameters for stability testing and sampling procedures aligned with IS 4905.
Guidelines for the packaging of foam concentrates include container material specifications (preferably stainless steel or as per manufacturer’s standards), labeling requirements, and storage conditions such as protection from direct sunlight, maintaining a dry and ventilated environment, and freeze protection measures.
Comprehensive test methodologies for sampling, physical and chemical property evaluation, and fire performance testing are provided. Sampling follows random selection protocols, and tests include measurement of pH, specific gravity, miscibility, sludge content, surface tension, and fire suppression capabilities.
Details on the use of the BIS Standard Mark, licensing conditions under the Bureau of Indian Standards Act, and manufacturer responsibilities for compliance and marking are included. The section also covers sample selection for type testing and related chemical and physical property requirements.
The standard specifies using n-heptane or commercial heptane mixtures with controlled distillation ranges and density for fire tests. Procedures for igniting the fuel, foam application duration, and equipment setup for fire performance evaluation are described.
Specifications for foam making nozzles, including capacity and operating pressures, are provided along with detailed procedures for foam generation, calibration, and expansion calculations. Equipment setups such as pressure vessels and measurement devices are described.
Methods for selecting samples from production batches, preparing composite samples, and conducting conformity tests against chemical, physical, and fire performance criteria are outlined.
This section elaborates on procedures to determine pH, specific gravity, miscibility, pour point, sludge content, and spreading coefficients, including sample conditioning and centrifuge testing parameters.
Fire performance tests measure foam expansion, drainage time, fire control and extinction times, burn back resistance, and sealability. Test setups and expected results for protein, fluoro-protein, AFFF, and Class A foams are discussed.
The standard describes procedures for determining surface tension of foam solutions and interfacial tension between foam solution and cyclohexane using the ring method, including preparation of reagents and calibration steps.
Formulas and procedures for calculating foam expansion and measuring the time for 25% liquid drainage from foam are detailed, including equipment specifications and data plotting techniques.
This test evaluates the ability of aqueous film-forming foams to create a protective film over hydrocarbon surfaces using a mild steel tray and stainless steel mesh drum, with criteria for fire resistance and film integrity.
The burn back test assesses the thermal stability and sealability of foam blankets by igniting fuel in a steel pot placed on the foam surface and recording the time for specified fire coverage, alongside other performance parameters.
Frequently Asked
IS 4989 (2006) specifies foam concentrates classified by their dilution ratios: Type 1 (1% concentrate), Type 3 (3% concentrate), and Type 6 (6% concentrate). These formulations cater to firefighting applications on Class A and Class B fires, focusing solely on top application methods. The standard integrates previous parts covering protein, aqueous film-forming, and fluoro-protein foams, while excluding alcohol-resistant and certain chemical foams.
Foam concentrates must meet defined requirements such as specific pH ranges (6 to 7.5 or 6.5 to 8.5 depending on type), specific gravity limits, complete miscibility with water, a pour point at or near zero degrees Celsius, controlled sludge content, and minimum spreading coefficients for certain foam types. Stability is verified by absence of sedimentation after aging and freeze-thaw cycles, and surface tension of foam solutions prepared with distilled water must be at least 70 mN/m.
Fire performance testing involves preparing foam solutions at specified dilutions, generating foam using standardized equipment as per Annex G, and applying it to standard fuel fires such as n-heptane. The tests assess extinguishing time, foam stability, burn-back resistance, and film formation. Advanced fire tests detailed in Annex K are conducted only if initial tests are passed to ensure cost-effective evaluation.
The standard prescribes using foam-making nozzles with a discharge capacity of 7.5 liters per minute at 7 kgf/cm² pressure, connected to a reservoir containing premixed foam solution and an air compressor supplying regulated pressure. The procedure includes filling the system with foam solution, adjusting pressure, and generating foam for testing purposes, with calibration and maintenance protocols ensuring consistent foam quality.
Foam concentrates should be stored in HDPE containers complying with IS 7959 or equivalent, clearly marked with manufacturer information, foam type, batch number, volume, and handling instructions. Storage conditions require protection from direct sunlight, a dry and ventilated environment, and temperature control to prevent freezing down to -20°C, ensuring product integrity and firefighting effectiveness.
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