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Restricted to standard solutions only, to ensure the site conditions do not conflict with the scope or limitations of the chosen standard solution. These may include standards trench boxes.

This applies to the use of standard solutions and not the original design, which requires both structural calculation and checking to Category 1, 2 or 3, as appropriate.

Because this is a site issue, the check may be carried out by another member of the site or design team.

• Kicker shutters, local and small scale shaping of the ground, small, single lift short duration access scaffolds controlled by ‘Scaftag’ or similar
• Shallow trenches, pits and excavated batters, not exceeding 1.2m depth with no significant overburden or groundwater.
• Low-rise formwork at ground/excavation level, max 2.4m double sided, 0.9m single sided 
• Non-design scaffolds to TG20:13xxi tables
• Site hoarding and fencing less than 2m high
• Other low risk items generally less than 1.2m high or 1.2m deep

1

For simple designs. These may include: formwork, falsework, needling and propping to brickwork openings in single storey constructions.

Such designs would be undertaken using simple methods of analysis and be in accordance with the relevant standards, supplier’s technical literature or other reference publications.

The check may be carried out by another member of the design team.

• Use of standard components to catalogue design
• Pits and trenches to CIRIA 97 Trenching Practice XXII
• Excavated slopes not exceeding 30deg incline or 2m height in free draining soil
• Designed scaffolds and loading platforms to TG20:13xxi tables
• Double sided formwork with access platforms at ground/excavation level
• Single sided formwork to 2.4m
• Routine formworks/falseworks at not more than 6m height, slabs not exceeding 500mm thick, beams not exceeding 1m width, 1.5m depth
• Mobile crane outrigger foundations in good ground crane to 50T
• Piling gates, simple and medium designs
• Permanent falsework e.g. metal decking
• Site hoarding and fencing greater than 2m high
• Concrete pumps outriggers with good access /good ground conditions

2

On more complex or involved designs. Designs for excavations including excavation support using sheet piles, for foundations, for structural steelwork connections, for reinforced concrete. Designs where stability is obtained by restraint at the top of the temporary works (e.g. top-restrained falsework).

Category 2 checks would include designs where a considerable degree of interpretation of loading or soils’ information is required before the design of the foundation or excavation support or slope is carried out.

The check should be carried out by an individual not involved in the design and not consulted by the designer.

• Departures from catalogue design for standard components
• Formwork and falsework at height greater 6m or for heavy suspended slabs and beams
• Falseworks requiring the use of bridging and similar heavy equipment
• Inclined formwork
• Special designed scaffolds
• Large, complex or unusual system formwork or falsework
• Cofferdams and sheet piled walls, contiguous piled temporary walls
• Excavation frames
• Underpinning sequences (routine)
• Slope stability and battered excavation; surcharging weak ground
• Demolition methods and temporary conditions - generally

3

For complex or innovative designs, which result in complex sequences of moving and/or construction of either the temporary works or permanent works. It also includes basement excavations and tunnels.

These designs include unusual designs or where significant departures from standards, novel methods of analysis or considerable exercise of engineering judgment are involved.

The check should be carried out by another organization and should include an overall check to assure co-ordination of the whole design.

• Temporary works combining inter-acting multiple designs
• Unusual concepts
• Bridge erection schemes and bridge temporary bracing
• Bridge demolition
• Structurally complex partial demolition or modification of existing structures
• Excavations and cofferdams in tidal conditions
• Excavations and cofferdams in poor ground (fill to deeper than 5m, water bearing fills)
• Large basement excavation and propping schemes
• Underpinning in poor soils, with surcharge and/or where the ‘pins’ act as retaining walls
• Pile and crane mats on poor ground (soft clays, water bearing soils, loose materials)
• Complex or suspended tower crane bases
• Components used as part of a crane or other mechanical equipment
• Hydraulic pressure pipework testing
• Pneumatic pressure pipework testing
• Abnormal stress cases in the permanent works resulting from temporary conditions
• Any scheme reliant on the ‘observational method’ or sensors and monitoring
• Assessment of structures likely to be affected by settlement or vibration caused by the method of work