Parameter
|
Open Cut Scenario
|
Pipe Jacking Scenario
|
|
Feasibility (& default)
|
As Designed
|
As Built
|
Feasibility (& default)
|
As Designed
|
As Built
|
|
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.
|
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
|
|