Code of practice for design and construction of fire service drill-tower
1970 Edition

Introduction to IS 5888 - Core Guidelines & Tables

Drill Tower Categories (Clause 3.1)

• Type A: Masonry construction suited for large stations; no hose drying or smoke chamber.
• Type B: Masonry design for small to medium stations, equipped with hose drying and optionally smoke chambers.
• Type C: Steel framework for small to medium stations including hose drying and smoke chamber capabilities.
• Type D: Steel construction for small to medium stations, facilitating both hose drying and drills, without smoke chambers; maximum hose drying length limited to 25 meters.

Floor Layout Dimensions (Clause 6.4.2)

• Internal floor area: 4.5 m by 4.5 m
• Clear drill space: 4.5 m by 2.25 m
• Remaining area allocated for hose drying after accounting for partition thickness

Drainage Provisions (Clause 6.6.5)

• Each floor must have drainage connected to external drainage systems.

Recommended Timber Species for Window Sills and Hose Toggles

*Treatability Grades: A=Easily treatable, B=Treatable, C=Partially treatable, D=Refractory, E=Highly refractory

Visual Summary of Tower Types

graph TD
A[Type A: Masonry, Large Stations] -->|No Hose Drying| NoSmokeChamber
B[Type B: Masonry, Small/Medium] -->|Hose Drying| SmokeChamber
C[Type C: Steel, Small/Medium] -->|Hose Drying| SmokeChamber
D[Type D: Steel, Small/Medium] -->|Hose Drying & Drill| NoSmokeChamber

Refer to applicable IS codes for steel, reinforcement, and aggregates for structural design details.

Scope Overview and Principal Specifications of IS 5888

• Coverage (Clause 3.1): Describes four drill tower varieties for fire stations:

  • Type A: Masonry for large fire stations, no hose drying or smoke chambers.
  • Type B: Masonry for small to medium stations, including hose drying and smoke chamber functions.
  • Type C: Steel for small to medium stations, equipped with hose drying and smoke chamber use.
  • Type D: Steel for small to medium stations, combining hose drying with drill facilities; includes removable floor boards for flexibility.

• Floor Size Requirements (Clause 6.4.2):

  • Overall internal dimension: 4.5 m × 4.5 m
  • Drill section: 4.5 m × 2.25 m
  • Remaining space (less partition thickness) designated for hose drying

• Functional Clauses (6.2.1 to 6.2.11): Applicable to all tower types.

Material and Fastener Notes (Referenced IS Standards)

• Structural steel: Ordinary quality grade
• Bolts and nuts: Black hexagon and square bolts/nuts ranging from 6 to 39 mm diameter
• Reinforcement bars: Mild steel, medium tensile, and hard-drawn wire per IS specifications
• Aggregates and sand: Conforming to IS standards for concrete and mortar

Diagram: Functional Floor Layout for Type D Tower

graph TB
    A[4.5m x 4.5m Floor]
    A --> B[Drill Area 4.5m x 2.25m]
    A --> C[Hose Drying Section]
    C --> D[Central Hose Suspension]
    B --> E[Removable Floor Boards for Adjustment]

Detailed design should align with IS 5888 clauses 6.2 and 6.4 and associated material standards.

Material Requirements and References According to IS 5888

• Mild Steel Flats and Sections (Clause 2.5): Mild steel complying with IS: 1977-1962 (Steel St. 32-0) is recommended for ladders and steel tower elements.

• Reinforcement Steel (Clause 2.7): Reinforcement must meet one of the following:

  • IS: 432 (Part I & II) - 1966 for mild and medium tensile bars
  • IS: 1139-1966 for cold-twisted bars
  • IS: 1566-1966 for hard-drawn steel wire
  • IS: 1786-1966 for high strength deformed bars

• Cement (Clause 2.4): Cement should conform to:

  • IS: 269-1967 for Ordinary Portland Cement
  • IS: 455-1967 for Portland Slag Cement

• Strength Considerations (Clause 2.1): Material strength must suit the specified design loads and tower functions.

Typical Characteristic Strengths (Reference Values)

flowchart TD
    A[Materials] --> B[Mild Steel per IS 1977]
    A --> C[Reinforcement per IS 432, 1139, 1566, 1786]
    A --> D[Cement per IS 269, IS 455]
    B --> E[Usage: Ladders and Tower Framework]
    C --> F[Usage: Concrete Reinforcement]
    D --> G[Usage: Concrete Mix]

Ensure use of IS-compliant, locally sourced materials for strength and longevity.

Categorization of Drill Towers and Design Guidelines as per IS 5888

The standard identifies four tower types—A, B, C, and D—each with dedicated design rules:

General Structural Considerations (Clause 6.2)

• Stability against wind and operational loads
• Appropriate material selection and sizing of components
• Foundation adequacy

Common Design Equations

• Wind Load Calculation: [ W = 0.6 \times V^2 \times A \times C_d ] Where:

  • (V) = design wind speed (m/s)
  • (A) = projected area (m²)
  • (C_d) = drag coefficient (from IS 875 Part 3)

• Buckling Checks: [ f_{allow} = \frac{f_y}{\text{Safety Factor}}, \quad \lambda = \frac{L_{eff}}{r} ] Use Euler’s formula or IS 800 limits for slenderness.

Summary Table of Tower Features

For detailed member sizing and design, consult the relevant clauses and figures.

IS 5888 Guidance on Site Selection and Location

Foundation Criteria (Clause 5.2)

• Foundations must rest on firm, hard strata.
• Must possess sufficient mass to resist overturning from wind forces.
• Steel superstructure should be anchored to steel posts embedded in substantial concrete blocks.
• Base cross members provide additional stability.

Drainage System (Clause 6.6.5)

• Each drill tower floor is equipped with drains.
• Drains connect to an external drainage network (Clause 6.2.9).

Platform Size Requirements (Clause 6.2.2)

Recommended Timber Species for Window Sills and Hose Toggles

Treatability Ratings:

• A: Easily treatable
• B: Treatable with limited penetration
• C: Partial treatability
• D: Refractory, requires incision
• E: Very refractory, negligible penetration

Conceptual Diagram: Site and Structural Stability

graph TD
A[Site Selection] --> B[Firm Foundation]
B --> C[Massive Foundation to Resist Overturning]
C --> D[Steel Posts Embedded in Concrete]
D --> E[Superstructure Anchored to Posts]
A --> F[Drainage Setup]
F --> G[Floor Drains]
G --> H[Connection to External Drain]

Essential Foundation Design Criteria in IS 5888

Foundation Requirements (Clauses 5.1 & 5.2):

• Foundations must be placed on firm, hard soil or rock.
• Must be sufficiently massive to counteract overturning caused by wind forces.
• Steel tower structures should be securely bolted to steel posts embedded in heavy concrete, with bracing cross members at the base for stability.
• Foundation design should consider soil characteristics in accordance with IS 1904-1966 (Code of Practice for Structural Safety of Buildings: Foundations).

Related Indian Standards for Materials:

• Aggregates for concrete: IS 383-1963
• Reinforcement steel: IS 1786 (hot-rolled deformed bars)
• Bolts and nuts: IS 1363 (black hex bolts), IS 1364 (black square bolts)

Foundation Design Overview:

Typical Stability Check Against Overturning:

[ \text{Overturning Moment} \leq \text{Resisting Moment} ]

• Resisting moment (M_r) calculated as:

[ M_r = W \times d ]

• Overturning moment (M_o) from wind load:

[ M_o = F_w \times h ]

Ensure foundation design satisfies ( M_r \geq M_o ).

Conceptual Diagram: Foundation Stability

graph LR
A[Wind Load (F_w)] -->|Generates Moment (M_o)| B((Tower Top))
B -->|Height (h)| C[Foundation Base]
C -->|Resisting Moment (M_r)| D[Foundation Mass (W)]

Note: Refer to IS 1904 for soil data and IS 456 for concrete mix design.

Fire Service Drill Tower Design Considerations per IS 5888

General (Clause 6.2)

• Ensure structural stability against wind and live loads.
• Utilize durable, weather-resistant materials.
• Provide safe means of access and exit.
• Include removable gratings and wooden shutters for openings.
• Fix steel uprights securely in ground for rope tie points.

Specifics by Tower Type:

Key Specifications:

• Removable Gratings: Cover floor openings for safety and access.
• Horizontal Rails: 750 mm high steel rails fixed on uprights for hose hoist rope attachment.
• Window Boards: 50 mm thick hardwood planks, 375 mm wide.
• Materials: Hardwood or light alloy sheets for slats and shutters.

Structural Focus:

• Calculate loads including live, wind, and operational forces.
• Ensure stability against overturning and sliding.
• Secure anchorage points for ladders and rails.

flowchart LR
    A[General Design Principles] --> B[Type A Tower]
    A --> C[Type C Tower]
    A --> D[Type D Tower]
    B --> E[Wooden Slats & Hinged Doors]
    C --> F[Removable Wooden Shutters]
    D --> G[Enhanced Structural Specifications]

Refer to IS 875 for load calculations and IS 800 for steel structure design.

General Functional Mandates for Drill Towers (IS 5888 Clause 6.2)

• Applicable to all tower types (A, B, C, D).
• Ensure suitability for firefighting training drills and hose drying.
• Design considerations include:
  • Structural integrity and safety.
  • Hose drying provisions.
  • Smoke chamber facilities where relevant.
  • Adequate floor usability.
  • Appropriate height for maximum hose length (up to 25 m for Type D).

Drill Tower Types Overview (Clause 3.1):

Summarized Functional Requirements (6.2.1 to 6.2.11):

• Sufficient floor area for drills.
• Hose drying racks or suspended systems.
• Compliance with steel and masonry standards.
• Safe access and egress.
• Use of removable floor boards in Type D for flexibility.
• Material compliance for steel, fasteners, and concrete reinforcement.

Functional Dimensions (from referenced figures):

• Tower height adequate for hose length and clearance.
• Floor area to accommodate simultaneous training.
• Hose drying arrangements centrally or laterally as per type.

Functional Summary Diagram

flowchart LR
    A[Drill Tower Categories]
    A -->|Type A| B[Masonry, Large Stations]
    A -->|Type B| C[Masonry, Small/Medium Stations]
    A -->|Type C| D[Steel, Small/Medium Stations]
    A -->|Type D| E[Steel, Small/Medium Stations]

    B --> F[No Hose Drying]
    B --> G[No Smoke Chamber]

    C --> H[Hose Drying Available]
    C --> I[Smoke Chamber Present]

Design Criteria for Type A Drill Towers (IS 5888 Clause 6.3)

• General Requirements: Follow Clause 6.2 plus specific provisions 6.3.1 to 6.3.5.

• Typical Structure: Comprises vertical supports, bracing members, and platforms engineered to withstand drilling activities and wind loads.

• Load Considerations: Include self-weight, operational drilling loads, wind pressures (per IS 875), and dynamic forces.

• Design Checks:

  • Axial capacity of vertical members.
  • Buckling resistance of compression elements.
  • Shear and bending stresses in bracing.
  • Connections designed per IS 800 requirements.

• Representative Formulas:

  • Axial Load Capacity: [ P_u = \frac{A \times f_y}{\gamma_m} ] where (A) is cross-sectional area, (f_y) is yield strength, and (\gamma_m) is the safety factor.

  • Buckling Load (Euler): [ P_{cr} = \frac{\pi^2 E I}{(K L)^2} ] where (E) is modulus of elasticity, (I) moment of inertia, (K) effective length factor, and (L) member length.

• Bracing Configuration:

graph TD
    A[Leg 1] --- B[Bracing]
    B --- C[Leg 2]
    C --- D[Bracing]
    D --- A

Refer to Fig. 1 and clauses 6.3.1–6.3.5 for detailed dimensions and member sizes.

Summary: Type A towers are designed by applying general principles with specific checks on axial load, buckling, and bracing strength using standard structural engineering formulas.

Design Guidelines for Type B Drill Towers (IS 5888 Clause 6.4)

Type B towers are lattice steel structures intended for fire service drills, supplementing general design rules (Clause 6.2) with specific criteria (6.4.1–6.4.5).

Key Design Aspects:

• Geometry: See Fig. 2 for typical tower shape and bracing arrangement.
• Loads: Design for axial compression, wind pressure, and equipment loads per Clause 6.2.
• Materials: Use structural steel conforming to IS standards, with corrosion protection.
• Bracing: Cross-bracing members resist lateral forces (Clause 6.4.3).
• Connections: Bolted or welded to transfer loads effectively (Clause 6.4.4).
• Foundation: Must withstand overturning and vertical loads (Clause 6.4.5).

Representative Load Calculations:

• Axial Capacity: [ P = A \times f_y ] where (A) is cross-sectional area and (f_y) is steel yield strength.

• Wind Load: [ W = C_w \times A_p \times V^2 ] where (C_w) is wind pressure coefficient, (A_p) projected area, and (V) wind velocity.

Summary Table:

graph TD
A[Foundation/Base Plate] --> B[Vertical Legs]
B --> C[Horizontal Braces]
B --> D[Diagonal Braces]
C --> D
D --> E[Top Platform & Equipment]

Refer to Fig. 2 and Clauses 6.4.1–6.4.5 for comprehensive design details.

Design Specifications for Type C Drill Towers (IS 5888 Clause 6.5)

Type C towers are steel lattice structures designed for drill activities, building on the general requirements in Clause 6.2 with additional guidance (6.5.1–6.5.3).

Primary Features:

• Geometry and Layout: Refer to Fig. 3 for typical bracing and member arrangement.
• Load Considerations: Include self-weight, drilling loads, wind forces, and dynamic effects.
• Material: Structural steel per applicable IS standards.

Design Provisions:

• Member Sizing: Use combined axial and bending stress checks:

  [ \sigma = \frac{P}{A} + \frac{M}{Z} \leq f_y ]

  where (P) = axial load, (A) = cross-sectional area, (M) = bending moment, (Z) = section modulus, and (f_y) = steel yield strength.

• Bracing: Designed to prevent buckling, conforming to IS 800.

• Connections: Bolted or welded per IS 800 standards to ensure stability.

Typical Member Design Data:

graph TD
A[Foundation Base] --> B[Vertical Legs]
B --> C[Bracing Members]
C --> D[Top Platform]

For precise dimensions and load details, consult Fig. 3 and clauses 6.5.1–6.5.3.

Type D Drill Tower Design Requirements (IS 5888 Clause 6.6)

Type D towers follow general design rules in Clause 6.2 with additional specific criteria (6.6.1–6.6.5).

Design Highlights:

• Structural Form: Typically a lattice steel tower with comprehensive bracing (see Fig. 4).
• Loads: Consider wind, drilling apparatus, and dynamic effects.
• Member Design: Use IS 800 for steel design, ensuring adequate section modulus and limiting slenderness.
• Bracing: Must meet lateral stability requirements.
• Foundation: Designed to bear combined axial and lateral forces.

Key Formulas:

• Axial Load Capacity: [ P = \frac{A \times f_y}{\gamma_m} ]

  where (A) is member cross-section, (f_y) yield strength, and (\gamma_m) safety factor.

• Buckling Criterion: [ \sigma_{allow} = \frac{\pi^2 E}{(K L/r)^2} ]

  where (E) is modulus of elasticity, (K) effective length factor, (L) member length, (r) radius of gyration.

Typical Parameters:

Conceptual Structural Layout

graph TD
A[Foundation] --> B[Lattice Legs]
B --> C[Horizontal Bracing]
C --> D[Diagonal Bracing]
D --> E[Top Derrick]

Consult IS 5888 Clause 6.6 and Fig. 4 for full design details; use IS 800 and IS 875 for member and load design.

Drainage and Safety Design Elements in IS 5888

Drainage Requirements

• Yard Surface Gradient (Clause 6.2.9): The ground around the drill tower should slope gently away toward a drainage channel covered with gratings to ensure efficient water runoff.

• Floor Drainage (Clauses 6.3.5 & 6.4.4.3): Each tower floor must have drainage directing water to external drainage at the base.

Safety Features (Figures & Clause 1.2)

• Removable Floor Gratings: Floor openings must be covered with removable wooden or metal gratings to prevent accidental falls while allowing emergency access.

• Guard Rails and Hoist Tie Points: Horizontal steel rails approximately 750 mm in height should be fixed on uprights for securing ropes during hose hoisting drills.

• Access Provisions: Entry is via mild steel ladders; windows use hinged wooden doors and wooden slats or light alloy sheets to provide ventilation and security.

Summary Table - Drainage and Safety Features

flowchart TD
    Yard_Surface -->|Slope| Grated_Channel
    Floor_1 -->|Drainage| External_Drain
    Floor_2 -->|Drainage| External_Drain
    External_Drain --> Drainage_System
    Safety_Features --> Guard_Rails
    Safety_Features --> Gratings
    Safety_Features --> Access_Ladders

These ensure proper water management and safety during fire training exercises.

Electrical Wiring and Installation Requirements as per IS 5888

• Internal Wiring: Must adhere to IS 732:1963, which governs electrical wiring installations up to 650 volts.
• Floor Dimensions (Clause 6.4.2):
  • Internal floor measures 4.5 m × 4.5 m.
  • Drill area: 4.5 m × 2.25 m.
  • Remaining space (less partition thickness) allocated for hose drying.
• Drainage (Clause 6.6.5): Each drill floor includes drains connected externally.
• Timber for Electrical Fixtures: Recommended species for window sills and hose toggles are provided with treatability ratings (A to E) indicating preservative treatment ease.

Electrical Wiring Summary per IS 732:1963

Approximate Current Capacity Formula:

[ I = k \times A ]

Where:

• (I) is current in amperes
• (A) is conductor cross-sectional area in mm²
• (k) depends on insulation and installation method (typically 6–10 A/mm² for copper)

Diagram: Electrical Wiring and Floor Layout

graph TD
    A[Internal Floor 4.5m x 4.5m]
    A --> B[Drill Area 4.5m x 2.25m]
    A --> C[Hose Drying Section (Remaining)]
    B --> D[Electrical Wiring per IS 732]
    C --> E[Drainage to External Drain]

Note: Electrical installation must be performed by qualified personnel in compliance with IS 732 and safety regulations.

Timber Specifications and Recommended Species for Window Sills and Hose Toggles (IS 5888)

Relevant Clauses:

• Clause 2.10: Mandates use of well-seasoned hardwood for window sill facings and hose suspension toggles.
• Clause 6.2.8: Specifies window sill thickness as 50 mm hardwood plank, firmly fixed with bolts or clamps.

Recommended Timber Species List (Appendix A)

*Treatability Grades Explained:

• A: Easily treatable
• B: Treatable with incomplete penetration
• C: Partially treatable
• D: Refractory; requires incisions
• E: Highly refractory; minimal penetration

Summary:

• Use 50 mm thick hardwood planks for window facings.
• Choose species based on availability and treatability.
• Ensure timber is well-seasoned and treated appropriately for durability.

flowchart TD
    A[Window Sill Facing] --> B[50 mm Hardwood Plank]
    B --> C{Select Timber Species}
    C --> D[Teak (E)]
    C --> E[Sissoo (E)]
    C --> F[Deodar (C)]
    C --> G[Hollock (A)]
    C --> H[Other Species per Appendix A]