| Materials |
| Number of shafts/manholes |
One at each end plus one every 100 m. | Specified by user. | Specified by user. |
One at each end plus one every 100 m. | Specified by user. | Specified by user. |
| Depth to invert | Equal across length of pipe, minimum 1.5 m depth. |
| Material exclusions | N/A | Gaskets, pointing & caulking (assumed to be insignificant quantities generated). Material contribution of interjacks to CO2e assumed to be zero (reusable). |
| Trench support | Steel plates, 6 mm thickness along trench sides, material contribution to CO2e assumed to be zero (reusable). | N/A |
| Trench fill | Virgin aggregate where "imported fill" specified. | N/A |
| Spoil | 70% soil (active) and 30% rubble (inert). |
| Asphalt | 300 mm thickness of asphalt applied where a highway site location is specified. | N/A |
| Installation |
| Number of machine hours |
Site closure duration (days) minus two (for setup and dismantling) multiplied by 8 operating hours (per day). | Specified by user. | |
Site closure duration (days) minus two (for setup and dismantling) multiplied by 8 operating hours (per day). | Specified by user. | |
| Machinery fuel type | Diesel (runs generator and excavator). | Diesel (runs generator, crane and air compressors in some setups). |
| Groundwater pump | Assumed to operate if groundwater presence specified. |
| Groundwater pump hours | Site closure duration (days) minus two (for setup and dismantling) multiplied by 24 operating hours (per day). |
| Ground type (work rate of machinery) | Rock (high – 0.7); Cohesive (medium – 0.54); Non-Cohesive (low – 0.38). |
| Transport |
| One way transport distances |
Aggregates – 41.9 km; Asphalt – 40.1 km; Apparatus – 113.5 km; Spoil – 30 km; Trench support – 100 km (x2 for drop-off and collection). | Specified by user. | Specified by user. |
Aggregates – 41.9 km; Asphalt – 40.1 km; Apparatus – 113.5 km; Spoil – 30 km. | Specified by user. | Specified by user. |
| Vehicle types | Aggregates, asphalt, spoil – Rigid HGV > 17 t; Apparatus, trench support – Articulated HGV > 33 t. |
| Vehicle utilisation | 50% for all journeys. |
| Exclusions | Emissions from the transport of plant and staff to and from site are excluded. |
| Traffic |
| Site location (daily traffic level) |
Minor Road – Rural (1000); Minor Road – Urban (2000); A Road – Rural (10000); A Road – Urban (20000); Non-Highway (0). |
N/A – assumed that pipe jacking operations are located off highway to minimise traffic disruption. Shafts located in roundabouts, footways and on brown or industrial land. |
| Site length | Rounded-up to nearest 50 m + 50 m e.g. 132 m pipe would be 200 m site length. | Specified by user. | N/A |
| Road type | 2-way single carriageway all purpose (S2AP) | N/A |
| Junction length | 1 km | N/A |
| Side roads intersecting | 2 per km | N/A |
| Closure type | 24 hour closure across site closure duration (days) | N/A |
| Speed limit | 30 mph | N/A |
| Proportion of HGVs | 5% | N/A |
| Converting carbon cost to mass | Use the 2011 non-traded central value in WebTAG (£158.87 per t of carbon) | N/A |