This part of BS1722 specifies requirements for steel palisade fences and gates for general purpose (GP) fences for heights up to 2.4m, and for security purpose (SP) fences for heights of 3m and 3.6m, all with posts at 2.75m centres. This British Standard also covers fences between 2.4m and 3m in height with components constructed to the SP specification. NOTE1 Where greater resistance against penetration is required for fences below 2.4m in height, the SP components should be obtained from the purchaser. NOTE2 Requirements in this British Standard for the minimum sizes of fence components are based on a design wind loading, q, at right angles to the plane of the fence of 900N/m 2 employing a shape factor of 1.9 on the net area presented to the wind. NOTE3 In situations of extreme exposure or abnormal loading, a special appraisal should be undertaken and the design criteria should be obtained from the purchaser. NOTE4 The responsibility for ensuring the final installation meets this British Standard belongs to the installer. This responsibility can be mitigated by obtaining certificates for materials used from the suppliers (see Clause 10 ).