BS 4485-4:1996

Committees responsible
Foreword
Section 1. General
1.1 Scope
1.2 References
1.3 Definitions
1.4 Symbols
1.5 Materials and workmanship
1.6 Packing support structures
1.7 Packings, water distribution systems, eliminators
      and cladding
1.8 Cooling tower fittings
1.9 Water retaining structures
1.10 Foundations and bases
Section 2. Hyperboloidal cooling towers (type 1 towers)
2.1 Basis of design
2.2 Loading
2.3 Design considerations
2.4 Construction
Section 3. Mechanical draught towers (type 2 towers)
3.1 Characteristic loads
3.2 Design considerations
Annexes
A (normative) Recommendations for stress graded
      timber triangular section laths
B (normative) Guidance on the use of plastics
      materials
C (informative) Wind tunnel testing
D (informative) Circumferential wind pressure
      distribution for hyperboloidal towers
E (normative) Estimation of resonant stresses
F (informative) Derivation of natural frequencies of
      hyperboloidal towers
Tables
1 Dimensional deviations of precast components
2 Coatings of metal components
3 Determination of lt and lp
4 Correction factors for stresses due to adjacent
      structures
5 Minimum reinforcement in shell
A.1 Permissible knot size for a 38 mm x 38 mm lath
Figures
1 Pressure coefficient distribution for determination
      of wind loading
2 Arrangement of reinforcement trimming for openings
      in shells
3 Arrangement of reinforcement in the shell
A.1 Splay knot
A.2 Arris knot
A.3 Face knot
F.1 Typical finite element representation of cooling
      tower with column supports
List of references

Applicable to structural design and construction on site of hyperboloidal shell natural draught towers, and to mechanical draught towers.

This Part of BS 4485 gives recommendations for the structural design and construction of water cooling towers of the following types: type 1. Natural draught or assisted draught towers, in which the total air flow is wholly or partly induced by a reinforced concrete shell of hyperboloidal form; type 2. Mechanical draught towers, in which the total air flow is induced wholly by mechanical means within an enclosed structure. It applies only to those cooling towers constructed or erected on site and excludes factory assembled towers. In addition, matters relating to construction and workmanship in concrete and other materials are dealt with only in so far as they are specific to cooling tower construction. Other items of construction are referred to in appropriate specifications. This code of practice covers the design of towers up to 170 m in height. However certain restrictions apply to formulae used for towers greater than 120 m in height. NOTE For cooling towers of type 1, shells similar in shape to the true hyperboloidal form may be considered. Where these other shapes are adopted then certain sections of this standard may not be strictly applicable.