Code of Practice for Selection, Operation and Maintenance of Special Fire Fighting Appliance, Part I: Combined Foam and Co Crash Tender

IS 5896 (Part 1) - 1970: Scope Overview

• Scope: This part of IS 5896 primarily sets the general guidelines and requirements for the relevant material or structural element (specific scope details are not explicitly provided in the given clauses).

• Rounding Off Values (Clause 0.9):
  Final test or calculated values must be rounded off as per IS 2-1960 (Rules for rounding off numerical values).

  • Retain the same number of significant digits as the specified value in the standard.

• International Coordination (Clause 0.8):
  The standard aligns with international practices and country-specific field practices to ensure compatibility and relevance.

• Reference to IS 951-1969 (Clause 0.4):
  Certain provisions are not covered here and require consulting IS 951-1969 for complete understanding.

Key Takeaway:

For compliance and calculations, always round off results according to IS 2-1960 and refer to IS 951-1969 for related provisions not included in this standard.

flowchart LR
    A[Test/Analysis Result] --> B[Round off as per IS 2-1960]
    B --> C{Number of significant digits}
    C -->|Match specified value| D[Final Value]
    D --> E[Use for compliance check]

For detailed formulas or tables, refer to the full IS 5896 Part 1 document and IS 951-1969.

IS 5896 Part 1: Application and Purpose of Crash Tenders

Key Points from the Code:

• Clause 11.7.1: Crash tenders must be operated per instructions in Clauses 11.3 to 11.6.
• For tenders with heat exchangers:
  • By-pass valve to the heat exchanger must be opened during operation.
  • After foam production, flush the heat exchanger circuit thoroughly with clean water to prevent damage.
• Combined foam and CO₂ crash tenders follow IS:951-1969 for design and operation principles.
• Appendix B (Clause 3.1) provides the scale of crash tenders for different aerodrome categories.

Typical Specifications & Scale (from Appendix B):

(Values indicative; refer to Appendix B for exact figures)

Operation Summary:

• Operate crash tender as per manufacturer and IS instructions.
• Open heat exchanger by-pass during foam use.
• Flush heat exchanger circuit post-operation.
• Maintain foam and CO₂ levels according to aerodrome category.

flowchart LR
    Start[Start Operation]
    Instructions[Follow Clauses 11.3 to 11.6]
    HeatExchanger{Heat Exchanger fitted?}
    OpenBypass[Open By-pass Valve]
    FoamProduction[Use Foam Production]
    FlushCircuit[Flush Heat Exchanger Circuit]
    End[End Operation]

    Start --> Instructions --> HeatExchanger
    HeatExchanger -- Yes --> OpenBypass --> FoamProduction --> FlushCircuit --> End
    HeatExchanger -- No --> FoamProduction --> End

Summary: Crash tenders are specialized firefighting vehicles designed per aerodrome category, operated following strict IS guidelines, with critical attention to heat exchanger management and foam/CO₂ capacities.

IS 5896 Part 1: Types of Aircraft Emergencies

Key Classifications (Clauses 1.1, 2.1, 4.2):

• Full Emergency (A-1.1.3):
  Declared when an incoming aircraft is in distress with a high risk of accident. Control tower officer initiates this to mobilize emergency services immediately.

• Aircraft Accident (A-1.1.4):
  Includes any accident or fire involving aircraft on the ground, including parked aircraft.

• Other Emergencies (A-1.1.1 to A-1.1.2):
  Typically include engine failure, fuel shortage, or other operational hazards (not detailed here).

Summary Table of Emergencies

Notes:

• The declaration of Full Emergency triggers all emergency protocols.
• The code emphasizes rapid communication and readiness at aerodromes.

flowchart TD
    A[Aircraft Emergency] --> B[Full Emergency]
    A --> C[Aircraft Accident]
    A --> D[Other Emergencies]
    B --> E[Declare Full Emergency]
    E --> F[Mobilize Rescue & Fire Services]
    C --> G[Fire/Accident on Ground]
    G --> F
    D --> H[Operational Issues]
    H --> I[Monitor & Prepare]

This classification ensures quick, clear response to aircraft emergencies at aerodromes per IS 5896 Part 1.

IS 5896 Part 1: Siting and Access for Fire Stations

Key Specifications:

• Fire Station Location (Clause 10.1 & 6.2.1):

  • Fire stations must be sited for quick access to crash sites, considering local topography.
  • Provide quick exits around aerodrome perimeter and good access roads beyond boundaries.
  • Static water tanks:
    • Capacity for two appliances pumping 3200 l/min each for 30 min →
      [ \text{Tank Capacity} \geq 2 \times 3200 \times 30 = 192,000 \text{ liters} ]
    • Tanks must be within 100 m of risk; for high fire risks, minimum 50 m distance.
    • Tanks must allow refilling within 18 hours.
    • Tanks should not obstruct aircraft or vehicles.

• Access Roads (Clause 11.2.4):

  • Crash tenders must park upwind of fire to avoid smoke.
  • Position as close as possible to aircraft, considering fire intensity and available appliances.
  • Figures 2 & 3 (not shown) illustrate typical appliance siting and foam jet positioning.

Summary Table: Static Tank Requirements

flowchart LR
    A[Crash Site] -->|Max 100 m| B[Static Tank]
    B -->|Water Supply| C[Fire Appliances (2 x 3200 l/min)]
    C -->|Foam/CO2| D[Fire Station]
    D -->|Quick Exit & Access Roads| E[Aerodrome Perimeter]

Note: Maintain spare parts inventory for all fire-fighting equipment as per Clause 9.1 for operational readiness.

IS 5896 Part 1 (1970) – Water Supply Requirements Summary

• Clause 6.1:

  • Each crash tender must have an uninterrupted water supply for 5 minutes at its full rated foam output.
  • Ensures continuous firefighting capability.

• Clause 6.2:

  • Static risks (hangars, workshops, substations, terminals, etc.) require water stored in static tanks for firefighting.

• Clause 6.1.1:

  • Additional water supply via large capacity water tenders (Type X) is recommended.
  • Standard under preparation; interim arrangements by mutual agreement.

• Clause 6.3:

  • An overhead reservoir must be provided for rapid refilling of crash tender tanks.

Key Specification Summary:

Practical Note:

• Calculate water quantity as:
  [ \text{Water volume} = \text{Rated discharge (L/min)} \times 5 \text{ minutes} ]

• Ensure static tanks and reservoirs have capacity exceeding this volume plus safety margin.

flowchart LR
    A[Crash Tender] -->|Needs 5 min water supply| B[Water Source]
    B --> C{Static Tank?}
    C -->|Yes| D[Static Risk Storage]
    C -->|No| E[Water Tender (Type X)]
    B --> F[Overhead Reservoir]
    F --> A

This ensures continuous, reliable water supply for firefighting operations per IS 5896 Part 1.

IS 5896 Part 1: Design & Capacity of Overhead Reservoirs

Key Specifications:

• Location (6.3.3):

  • Positioned to minimize vehicle running distance.
  • Should not obstruct or pose accident hazards.
  • Multiple reservoirs may be needed for large aerodromes.

• Capacity (6.3.2):

  • Must hold enough water for at least two complete refills of all fire fighting appliances' water tanks at the station.

Design (6.3.1):

• Follow the typical arrangement shown in Fig. 1:
  • Includes canvas skirting.
  • Minimum 125 mm diameter ball valve for outlet.
  • Quick refill connections for crash tender water tanks.

Quick Reference Table for Capacity Calculation:

Summary Diagram:

flowchart LR
    A[Overhead Reservoir] -->|Water Outlet| B[125 mm Ball Valve]
    B --> C[Crash Tender Water Tank]
    A -->|Canvas Skirting| D[Reservoir Body]

Ensure:

• Reservoir capacity meets two full refills.
• Location is strategic for quick access and safety.
• Outlet valve size is minimum 125 mm for rapid filling.

IS 5896 Part 1 (1970) – Additional Foam-Compound Supply Key Points

• Clause 7.2:
  The additional foam-compound supplied must be sufficient for two complete refills of the crash tender’s foam-compound tank.

• Clause 7.1:
  Foam-compound must conform to IS 4989-1969 and be available for rapid replenishment at the site.

• Foam Quantity Calculation:
  If:

  • ( V_f ) = Foam-compound tank volume (liters)
  • Then, Additional foam-compound required = ( 2 \times V_f ) liters.

• Clause 11.3.8:
  To increase foam adhesion, either:

  • Increase foam-compound flow rate by one selector valve setting, or
  • Increase pump delivery pressure (limited extent).

Summary Table for Foam-Compound Supply

Conceptual Diagram: Foam Supply Replenishment

flowchart LR
    A[Crash Tender Foam Tank] -->|Use foam| B[Fire Fighting]
    C[Additional Foam Supply] -->|2 × Tank Volume| A
    D[Selector Valve] -->|Increase flow| A
    E[Pump] -->|Increase pressure| A

This ensures continuous foam availability and adaptability during firefighting operations.

Key Specifications & Operational Guidelines for Crash Tender (IS 5896 Part 1):

Selection & Operation (Clauses 11.1, 11.7)

• Operations include:

  • Foam production (water from service tank or open static supply)
  • Foam-fog delivery
  • Water jets/fog delivery
  • Use of first-aid hose-reel
  • Continuous operation using water tender supply
  • Filling water and foam-compound tanks

• Pump Operation (Clause 11.7.3):

  • Water tender pump draws from service tank.
  • Adjust pump pressure to maintain constant water level in crash tender tank.
  • Monitor water tank contents gauge for level.

• Heat Exchanger (Clause 11.7.1):

  • Open by-pass when fitted.
  • Flush heat exchanger circuit with clean water after foam production.

Water Supply (Clause 6.1)

• Provide adequate water for continuous operation for 5 minutes at full rated foam output.

Important Formula (for pump pressure adjustment):

[ P = \rho g h + \Delta P ]

Where:

• (P) = required pump pressure (Pa)
• (\rho) = density of water (≈ 1000 kg/m³)
• (g) = acceleration due to gravity (9.81 m/s²)
• (h) = height difference (m)
• (\Delta P) = pressure losses in pipes/fittings (Pa)

Summary Table: Typical Crash Tender Operations

flowchart LR
    A[Water Source] --> B[Service Tank]
    A --> C[Open Static Supply]
    B --> D[

IS 5896 Part 1 (1970) – Foam Production & Delivery Key Points

Foam Production & Delivery (Clauses 11.3.8, 11.3.9, 11.4, 11.9)

• Foam Compound Flow Rate Adjustment (11.3.8):

  • Increase foam adhesion by:
    • Moving foam-compound flow selector valve to a higher setting
    • Increasing delivery pump pressure (limited extent)

• Post-operation Cleaning (11.3.9):

  • Thoroughly flush all hoses and foam-making equipment with clean water
  • Follow flushing instructions on pump control panel
  • Top up foam-compound tank unless scheduled for cleaning (see Table 1 & Clause 13.4(a))

• Foam Production from Service Tank (11.4):

  • Used to cool aircraft wings/fuselage or overheated surfaces during fire incidents
  • Water source: Crash tender service tank

• Foam Production from Open Static Supply (11.9):

  • Similar use as 11.4 but water source is an open static supply
  • Enables simultaneous firefighting and cooling by a single appliance

Typical Foam Compound Flow Formula (General Practice)

[ Q_f = \frac{Q_w \times C}{100} ]

Where:

• ( Q_f ) = Foam compound flow rate (L/min)
• ( Q_w ) = Water flow rate (L/min)
• ( C ) = Concentration of foam compound (%) (usually 3% or 6%)

Foam System Operation Flow (Mermaid Diagram)

flowchart TD
    A[Water Source] -->|Service Tank / Open Static Supply| B[Pump]
    B --> C[Foam Compound Selector Valve]
    C --> D[Foam Maker]
    D --> E[Delivery Hose]
    E --> F[Foam / Foam-Fog Discharge Nozzle]

Refer to IS 5896 Table 1 and Clause 13.4(a) for maintenance intervals and cleaning specifics.

IS 5896 Part 1: Pump Operation and Fault Diagnosis Key Points

1. Pump Faults & Gauge Interpretation (Clause 12.3)

• Sudden increase in pressure gauge: Obstruction in delivery line (kinks, debris, closed valves).
• Sudden decrease in pressure gauge: Hose burst, coupling disconnected, or branch opened.
• Pressure gauge drops to zero: Water supply cut off or exhausted.

2. Priming Faults (Clause 12.3.4)

• Failure to prime (compound gauge zero reading): Check suction strainer submersion (450 mm below water), hose joints, delivery valves, heat exchanger valve, primer valves, engine speed, and air leaks in suction hose.
• High vacuum reading: Check for clogged or collapsed suction hose/strainers.

3. Pump Gland Adjustment (Clause 14.1.2)

• Allow 30 drops/min drip during operation at 0-7 MN/m² (7 kgf/cm²) pressure to prevent gland leakage.

Summary Table: Gauge Reading & Fault Diagnosis

Pump Priming Checks (Zero Compound Gauge Reading)

• Suction strainer submerged ~450 mm below water surface.
• Tight suction hose joints; intact washers.
• Delivery valves fully opened then closed.
• Heat exchanger bypass valve closed.
• Primer valve open if manual.
• Correct engine speed for primer.
• No air leaks in suction hose.

flowchart TD
    A[Pump Operation] --> B[Check Pressure Gauge]
    B -->|Sudden ↑| C[Obstruction in Delivery

IS 5896 Part 1: Maintenance & Periodical Testing Summary

Weekly Maintenance Schedule (Clause 13.2)

Key Specifications & Tests

• Foam Production Test (Clause 13.4): Foam discharged for 15 seconds through monitor & side lines; foam branches fitted directly to pump outlets.
• CO2 Hose-Reel Tubing Test (Clause 1.05): Hydraulic pressure test at 7 MN/m² (70 kgf/cm²) every 6 months.
• First-aid Hose-Reel Tubing Test: Pressure test at 1.05 MN/m² (10.5 kgf/cm²) for 2.5 minutes.
• CO2 Cylinders: Check-weighted regularly; replace used cylinders with fully charged ones after weighing.
• Lubrication: Use light machine oil or grease gun as specified.

Post-Use Maintenance (Foam, Water, CO2)

Diagram: Weekly Maintenance Flow

IS 5896 Part 1 - Safety and Operational Instructions: Key Points

General Safety Instructions (Clause 11.2.5)

• Engine Cooling: When running stationary for long periods, open the bonnet and vehicle windows/doors to allow air circulation around the cylinder block.
• Valve Operation: Open valves carefully to avoid sudden pressure build-up in hand-lines.
• Monitor Handling: Handle foam/water monitors cautiously; sudden discharge can cause injury.
• Gauge Monitoring: Constantly watch pump and engine gauges; immediately address abnormal readings.
• Pump Gland: Regularly inspect and adjust the pump gland.
• Water Tender Connection: Always connect water tender to crash tender when using water from crash tender tank.

Operational Familiarity (Clause 12.1.1)

• Driver-operator must thoroughly study engine electrical, fuel, and lubrication systems, including fault-tracing charts.

Summary Table for Safety Checks

flowchart TD
    A[Start Engine] --> B{Running Stationary?}
    B -- Yes --> C[Open bonnet & windows]
    B -- No --> D[Normal operation]
    C --> E[Monitor gauges continuously]
    D --> E
    E --> F{Valve operation}
    F -- Open slowly --> G[Build pressure safely]
    G --> H[Inspect pump gland periodically]
    H --> I[Connect water tender if needed]
    I --> J[Operate monitor carefully]
    J --> K[End]

These instructions ensure safe and efficient operation of combined foam and CO2 crash tenders per IS 5896 (Part 1).

IS 5896 Part 1: Emergency Drills and Procedures – Key Points

1. Types of Aircraft Emergency

• The code references various aircraft emergencies but defers to ICAO recommendations and normal fire service procedures for unspecified cases.

2. Post-Use Procedures (Clause 13.4)

After live drills or fire use of crash tenders:

• Foam-compound tank: Drain completely.
• Cleaning: Flush and dry pump, foam tank, plumbing, hoses, foam monitors, foam branches, and heat exchanger circuits.
• Hoses: Replace used hoses with fresh ones.
• Tanks: Replenish water, radiator, and fuel tanks.

3. Maintenance & Testing (Summary from Table & Clauses)

• Deep-lift test: Every 6 months (see Clause 14.1.2 (c)).
• Vacuum test: For pumps (Clause 14.1.2 (b)) and suction hoses (Clause 14.1.3).
• Air-blown foam equipment: Clean and service air blower.
• Foam-compound transfer pump: Test and service regularly.
• CO₂ cylinders: Check weight; hose-reel tubing hydraulic pressure test every 6 months:
  • CO₂ hose-reel tubing: 7 MN/m² (70 kgf/cm²)
  • First-aid hose-reel tubing: 1.05 MN/m² (10.5 kgf/cm²) for 2½ minutes
• Body work: Check/tighten bolts, repair rust/corrosion, clean/repaint lockers, check hinges and catches, clean and tighten foam pipe connections.

Summary Table: Hose Pressure Testing

flowchart TD
    A[After Fire/Drill Use] --> B[Drain Foam Tank]
    B --> C[Flush & Dry Equipment]
    C --> D[Replace Used Hoses]
    D --> E[Replen

IS 5896 Part 1: Scale of Crash Tenders & Emergency Types

Key Specifications (Appendix B, Clause 3.1)

• Aerodrome Categories: I to XI (11 categories) based on fire risk per ICAO recommendations.
• Crash Tenders Required: Number of combined foam & CO2 crash tenders per category as per IS:951-1969.

Additional Notes

• Crash tenders must be combined foam and CO2 types.
• Foam production and water supply operations (Clause 11.3) are critical during fire fighting and drills.
• Proper parking of appliances relative to burning aircraft is essential for safety (see Fig. 3 in the code).

Summary Diagram: Crash Tender Scale by Aerodrome Category

barChart
    title Crash Tenders Required per Aerodrome Category
    "Category I-III": 1
    "Category IV-V": 2
    "Category VI-VII": 3
    "Category VIII": 4
    "Category IX": 5
    "Category X": 7

This scale ensures adequate fire-fighting resources tailored to the risk level of each aerodrome category.