Functional Requirements for Rescue Tender for Air Fields

IS 956 Scope: Key Specifications & Equipment

Scope Summary:

IS 956 covers Airfield Rescue Tenders (ART) specifying:

• Performance & Dimensions (Clause 5.4):

  • Acceleration:
    • Class 1: 0–80 km/h in 25 s
    • Class 2+: 0–80 km/h in 40 s
  • Max speed: 105 km/h
  • Approach/departure angle: ≥ 30°
  • Inter-axle clearance: ≥ 458 mm
  • Under-axle clearance: ≥ 230 mm
  • Side slope: 53%
  • Gradability: 50%
  • Stability angle: ≥ 30°
  • Fordability: 608 mm
  • Turning radius: < 3 × ART length
  • Braking distance: 10.7 m at 32 km/h (full load)

• Pump capacity: Minimum 4000 LPM at 8.5 kg/cm²

• Drive: Preferably all-wheel, right-hand drive

Equipment Schedule (Clause 12.4):

(Full list includes tools, hoses, nozzles, safety gear, and rescue equipment.)

Markings (Clause 2.5 & Annex B):

• Airport Fire Service
• Year of manufacture
• Engine & chassis number

IS 956: Normative References Summary

Annex A (Clause 2) lists key Indian Standards (IS) referenced for firefighting equipment and components:

Key Specifications from IS 956

• Pump capacity: Minimum 4000 LPM at 8.5 kg/cm²
• Acceleration:
  • Class 1: 0–80 kmph in 25 s
  • Class 2+: 0–80 kmph in 40 s
• Clearances:
  • Inter-axle: ≥ 458 mm (12° min)
  • Under-axle: ≥ 230 mm
• Angles:
  • Approach/departure: ≥ 30°
  • Side slope: 53%
  • Stability: ≥ 30°
• Turning radius: < 3 × length of ART
• Braking efficiency:
  • 10.7 m at 32 kmph (full load)
  • 40 m at 64 kmph

Marking Requirements on Vehicle Body

• Airport Fire Service
• Year of manufacture
• Engine and chassis number
• Fire service emblem
• Job or SI

IS 956 - Performance Requirements Summary

Key Notes:

• Rims, tyres, wheels, and inflation pressures must be approved by manufacturers (Clause 6.8.4).
• Manufacturer guarantees replacement of defective parts during warranty (Clause 13.3).
• Equipment and marking specifications are detailed for operational readiness.

Braking Efficiency Formula (conceptual):

[ \text{Braking Distance} = \frac{v^2}{2 \mu g} ]

Where:

• (v) = velocity (m/s)
• (\mu) = coefficient of friction
• (g) = acceleration due to gravity (9.81 m/s²)

Turning Circle:

• Must be less than 3 times the length of the Airfield Rescue Tender (ART).

graph LR
A[Acceleration] --> B[Class 1: 0-

IS 956: Materials and Construction - Key Points

Materials Specifications (Clause 4.5)

• Waterways & foam-contact parts: Stainless steel only.
• Metal pipelines & fasteners: Stainless steel.
• Exposed metal parts: Corrosion-resistant or suitably treated.
• Ferrous fasteners: Galvanized or chrome plated to prevent rust.

Construction Quality (Clause 4.1)

• Use new, defect-free materials.
• Materials selected for lightness, strength, and durability.

Equipment & Material Standards (Annex A & Clause 12.4 Table)

Markings (Clause 12.4)

• Airport Fire Service
• Year of manufacture
• Engine & chassis number
• Fire service emblem
• Pump capacity & SI No.
• Supplier & country of origin
• Safety & precaution instructions

Summary Table: Material Requirements

This ensures durability, corrosion resistance, and compliance with firefighting equipment standards per IS 956.

IS 956 — Key Weights & Dimensions (Clause 5.4 & related)

Weight Distribution (Clause 5.2)

• Weight difference between tyres on same axle ≤ 5% of average tyre load.
• Weight difference between axles ≤ 10% of heaviest axle load.
• Do not exceed axle or tyre manufacturer ratings.

Additional Notes (Clause 4.5)

• Waterway parts & foam-contact surfaces: stainless steel.
• Metal pipelines & fasteners: stainless steel or corrosion-resistant.
• Ferrous fasteners: galvanized/chrome plated.

Summary Diagram: Vehicle Clearance & Angles

graph LR
A[Vehicle Front] -->|Approach Angle ≥ 30°| B[Obstacle]
C[Vehicle Rear] -->|Departure Angle ≥ 30°| D[Obstacle]
E[Under Vehicle]

IS 956 Key Specifications & Formulas: Vehicle Systems and Components

1. Vehicle Electrical System (Clause 6.5)

• Vehicle electrical system options:
  • 12 V electrical and starting
  • 24 V electrical and starting
  • 12 V electrical and 24 V starting

2. Vehicle Drive (Clause 6.6)

• Drive on all wheels (preferably right-hand drive)

3. Weights and Dimensions (Clause 5.4, Table 5)

Braking Efficiency Formula (for reference)

[ \text{Braking Distance} = \frac{V^2}{2gf} ]

• (V) = velocity (m/s)
• (g) = acceleration due to gravity (9.81 m/s²)
• (f) = coefficient of friction (depends on surface and brake system)

flowchart LR
    A[Vehicle Systems] --> B[Electrical System]
    A --> C[Drive System]
    A --> D[Weights & Dimensions]
    B --> E{Voltage Options}
    E --> F[12 V

IS 956: Body and Equipment Storage - Key Specifications

Body Construction (Clause 7.1)

• Use lightweight materials ensuring strength for off-pavement, rough terrain, and heat exposure.
• Body types:
  • Unitized with chassis rigid structure
  • Flexible mounted on chassis
• Include front and rear tenders or wheel wells.
• Body panels must be removable for interior access.

Equipment Storage (Clause 7.3)

• Provide lighted compartments for equipment/tools.
• Compartments must be water-tight and self-draining.

Key Dimensions & Performance (Clause 5.4)

Water Tank (Clause 8.8.1)

• Rated capacity: 4000 litres
• Outlet design to use 85% capacity on:
  • 20% side slope
  • 30% ascending/descending slope

Summary Diagram: Body & Storage Requirements

graph LR
A[Body Construction] --> B[Lightweight & Strong Materials]
A --> C[Unitized or Flexible Mount]
A --> D[Removable Panels]
E[Equipment Storage

Key Specifications & Formulas for Firefighting Systems (IS 956)

1. Foam Production Requirements (Clause 3.5):

• Minimum Expansion Ratio: 1:8 (Foam volume to liquid volume)
• Drainage Time: 25% drainage in 3 minutes for Aqueous Film Forming Foam (AFFF)

2. Paint Finish (Clause 7.8):

• Color: Fire Red
• Resistance: Must resist damage from firefighting agents

3. Manufacturer's Responsibilities (Clause 13.3 & 14):

• Guarantee replacement of defective parts free within guarantee period
• Spare parts availability for at least 10 years
• Provide manuals: Operator, Parts, Repair, and General Arrangement drawings
• Markings on vehicle: Fire service emblem, capacity, year, chassis no., warnings, etc.

4. Essential Equipment & Tools (Clause 8):

• Suction hoses, strainers, wrenches (IS 5612)
• Branch pipes, nozzles, foam making branch pipes (IS 2097)
• Fire hooks (IS 927), hacksaw, axes, hydraulic cutter, breathing apparatus
• Aluminium extension ladder (10.5 m), electric generator (10 kVA petrol)

5. Referenced IS Standards for Components:

Foam Expansion Ratio Formula

[ \text{Expansion Ratio} = \frac{\text{Volume of Foam}}{\text{Volume of Liquid Foam Solution}} ]

Minimum acceptable: 8

Diagram: Foam Production System Overview

flowchart LR
    A[Foam Concentrate] --> B[Mixing with Water]
    B --> C[Foam Solution]
    C --> D[Foam Generator (Monitor/Hand Line)]
    D --> E[Foam Expansion (Min 1:8)]
    E --> F[Application on Fire]

IS 956: Controls and Instrumentation (Clause 6.14 Highlights)

• Illumination:

  • All instruments and controls must be illuminated.
  • Backlighting is preferred where practical.
  • Pump pressure and compound gauges must be glycerine filled for damping.

• Minimum Instruments/Warning Lights (Clause 6.14.4):

  • Speedometer/odometer
  • Engine tachometer
  • Fuel level indicator
  • Air pressure gauge
  • Engine temperature indicator
  • Engine oil pressure gauge
  • Volt meter
  • Trafficator light
  • Transmission oil temperature indicator
  • Pump pressure gauge
  • Water tank level indicator
  • Foam tank level indicator
  • Low air pressure warning indicator
  • Headlight beam indicator
  • Hazard warning light
  • PTO engagement light
  • Oil temperature gauge light

• Grouping & Accessibility (Clause 6.14.1):

  • Chassis instruments/warning lights grouped on a panel in front of the driver.
  • Firefighting system instruments/warning lights grouped by function for easy access and visibility to driver and crew.

Summary Table of Key Instruments

flowchart LR
    A[Driver Panel] --> B(Chassis Instruments)
    A --> C(Firefighting Instruments)
    B --> D{Speed

IS 956: Communication Systems Key Points

• Clause 6.5.9:

  • Electromagnetic interference (EMI) from vehicle electrical systems must be suppressed to avoid disrupting radio communication.
  • Use shielding, proper grounding, and filters to minimize EMI effects on radio sets.

• Clause 10.3:

  • Global Positioning System (GPS) provision is recommended for satellite communication and remote navigation.
  • GPS integration improves operational efficiency and safety.

• Clause 9.3:

  • Visual indicators (lamps) for engine, PTO pump, and pneumatic circuit functions should be installed in the driver’s cabin for easy monitoring.

Typical EMI Suppression Measures (per IS and engineering practice):

Communication System Checklist:

• EMI suppression per Clause 6.5.9
• Visual indication lamps per Clause 9.3
• GPS provision per Clause 10.3

flowchart LR
    Electrical_System -->|EMI| Radio_Set
    Radio_Set -.->|EMI Suppression| Electrical_System
    Driver_Cabin -->|Visual Indication| Engine/PTO/Pneumatic
    Communication_System --> GPS

Summary: Ensure EMI control, visual function indicators, and GPS integration for compliant communication systems in vehicles per IS 956.

IS 956 Key Specifications for Extinguishing Agents

• Primary Agents:

  • Foam concentrate and dry powder (ABC type, foam compatible).
  • Dry powder conforms to IS 14609.
  • Foam compatible dry powder ensures no reaction with foam.

• Dry Chemical Powder Units (Clause 11.1):

  • Quantity: Two units of 125 kg each.
  • Propellant: Dry nitrogen.
  • Minimum throw: 8 m.
  • Discharge rate: 1.5 kg/s.

• Complementary Agents (Clause 8.1 & 11.6):

  • Suitable halon substitute or CO2.
  • Halon substitute must conform to relevant Indian Standards.

• Auxiliary Dry Powder Handlines (Clause 8.11.5):

  • Nozzle discharge rate: 1.5 to 3 kg/s.
  • Throw range: 8 m.
  • Nozzle material: Non-ferrous metal or stainless steel.

Summary Table

flowchart LR
    A[Primary Agents] --> B[Foam Concentrate]
    A --> C[Dry Powder (ABC, Foam Compatible)]
    C --> D[Conforms to IS 14609]
    A --> E[Complementary Agents]
    E --> F[Halon Substitute / CO2]
    G[Auxiliary Handlines] --> H[Discharge Rate 1.5-3 kg/s]
    G --> I[Throw 8 m]
    G --> J[Nozzle Material: Non-ferrous/Stainless Steel]

This ensures compliance with IS 956 for effective fire extinguishing agent selection and deployment.

IS 956 Additional Equipment for Airfield Rescue Tenders

Key Equipment & Specifications (Clause 12.4, Annex B)

Additional Items Include:

• Sledge hammer (1.8 kg), axes

IS 956: Manufacturer's Certificate & Guarantee (Clauses 13.1 - 13.3)

• Manufacturer's Certificate (13.1): Must confirm appliance compliance with all specifications.
• Guarantee Period (13.2): 12 months from delivery date covering material, workmanship, and smooth functioning.
• Replacement Responsibility (13.3): Manufacturer must replace defective parts free of charge if due to sub-standard materials or workmanship during guarantee.

Product Support (Clause 14):

• Spare parts availability for at least 10 years.
• Induction training for staff at supplier's cost.
• Technical and after-sales support.
• Provide literature/manuals (1 set with equipment + 3 sets for training):
  • Operator’s Manual (technical details, operation, maintenance)
  • Parts Manual (exploded views, part numbers)
  • Repair Manual (repair/overhaul instructions)
  • General arrangement drawings.

Markings on Vehicle Body:

• Airport Fire Service, Year of Manufacture, Engine/Chassis No.
• Fire service emblem, Job/SI No., Pump & tank capacities.
• Supplier info, Left hand drive warning, Precautionary instructions.

Summary Table: Guarantee & Support

This ensures compliance, durability, and operational readiness per IS 956.

IS 956: Product Support & Documentation Key Points

1. Product Support (Clause 14)

• Spare parts availability: Minimum 10 years at short notice.
• Training: Induction training at supplier's cost.
• Technical help: During induction and after-sales service.

2. Documentation to be Provided (One set per equipment + 3 sets for inspection/training)

• Operator's Manual: Equipment description, layout, commissioning, operation, maintenance, lubrication, fault finding, storage, warnings.
• Parts Manual: Exploded views, part numbers, source of supply.
• Repair Manual: Repair/overhaul instructions, fitment tolerances, special tools, dismantling procedures.
• General Arrangement Drawings: Layout of equipment, piping, electrical, structural design.

3. Markings on Vehicle Body

• Airport Fire Service, Year of Manufacture, Engine/Chassis No., Fire Service Emblem, Job/SI No., Pump & tank capacities, Supplier info, Left hand drive warning, Precautionary instructions.

4. Relevant IS Standards for Equipment & Tools (Annex A & Schedule B-1)

• Examples:
  • IS 14933: Fire fighting hose
  • IS 907: Suction strainers
  • IS 903: Nozzles & couplings
  • IS 2097: Foam making branch pipe
  • IS 5714: Stand pipes
  • IS 3650: Insulated gloves

5. Performance & Dimensional Specs (Clause 5.4)