Vacuum excavation is a safe excavation method that aims to reduce cable strikes. It uses suction to excavate soil instead of traditional digging techniques. Vacuum excavators can excavate safely around utilities and in confined spaces. They are faster than manual excavation, more productive, cost less than strikes or accidents, and cause less disruption than traditional equipment. Vacuum excavation is well-suited for tasks like installing trenches, pipelines, and trial holes near airports, roads and utilities. It protects infrastructure and workers while providing an innovative alternative to traditional excavation.
2. Vac-Ex
Intro:
Vacuum excavation is known to be the safest method for
excavation in terms of human health and safety and the
protection of infrastructure.
Suction excavator technology aims to help reduce cable
strikes across the industry and meet, legal and moral
obligation of clients and contractors.
Construction industry is ever increasing demands for safe,
innovative, cost effective and environmentally friendly
solutions.
Civil engineering, utility and construction companies
should identify Vacuum as a more reliable (fit for
purpose), safe and fast solutions on the most complex of
projects due to the fact that Vac-ex is a low risk
alternative to traditional excavation techniques (Open-
Cut, Expose and Repair). Vacuum Excavation
(Building the Brighton i360,
2014)
3. Where can
Vacuum
Excavation be
used?
• Airports
• Highways
• Rail
• Water
• Gas
• Power
• Nuclear
• Tree root excavation
• Installing trenches &
pipeline
• Archaeology (with
reduced suction/blow
power)
• Excavating safely
around existing utilities
• Trial holes
• Shallow shaft
excavation (entry pit
and receiving pit for
HDD)
• Reactive emergency
service.
Vacuum
Excavation
Vacuum Excavators can be
commonly (since wheeled) used
in:
4. Some Advantages:
• Reduce the number of workers on site with our vacuum excavators and especially avoid any
manual digging and access to the pit/trench form anyone.
• Fast excavation is guaranteed without the risk of affecting or damaging any unforeseen utilities.
• Reduced size of excavation since no damage or strike could incur to the buried duct/pipe.
• Reduced compound/working area and less disruption to the public.
• Increased productivity and less plant and workforce on site.
• No requirement for mobilization and demobilization and does not need even an attendant
dumper.
• Vacuum Excavators internal spoil self-storage capacity up to 12m3.
• Reduced insurance premium for contractor using this technology (utilities strike is one of the top 5
cost pressure for insurers and therefore reflected to the final cost of the client).
• Environmentally friendly since Vacuum Excavators reduce carbon footprint (one plant instead of
at least two – based upon trench bottom depth n.e. 1.2m with stiff soil condition or hard rock).
• Vacuum Excavation technology reduces noise and disruption to residents (compared to a 9t
excavator and a 4t dumper) and limits vibrations that could possibly lead to damages on or
around the site.
• Can access remote or confined space area with minimal human exposure to hazard or difficult
access egress situations.Vacuum Excavators can be operated remotely.
(lmdvacuumexcavation, n.d.)
Vacuum Excavation
5. Productivity
Vacuum
Excavation
At the smaller end of Vacuum Excavators market
there are the lower power, smaller capacity units
(typically 0.25m3 to 1m3 capacity) that are
suitable for small excavation works and trial holing
with production rates of no more than 5
excavations per day.
Considered nine hours shift and including the
downtime to set up the plant (mainly towed and
connected to a generator, induction and breaks). It
could aim to have up to six net working hours with
an excavation rate to expose the service of 0.85m3
per hour.
In the 7t/10t truck mounted, the units have a
spoil capacity of around 1m3 to 2m3.
Typically used for smaller service pits and
trial holing, the units have a lower
performance and so are better suited to
easier ground with usually around 5/7 pits
per day being an average production rate.
Considered nine hours shift and including the
downtime to set up the plant (positioning in
place and break up the surface, induction and
breaks). It could aim to have up to six net
working hours with an excavation rate to
expose the service of 1.75m3 per hour.
(vac-ex.com, n.d.)
6. Productivity
“City Rigs” are truck mounted on a
16t/18t; the units have a spoil capacity
capacity of between 2.5m3 to 4m3.
Typically used for multiple utility service
pits they can perform in excess of 8
excavations per day at depths of up to
to 10m to 15m being possible.
Considered nine hours shift and
including the downtime to set up the
plant (positioning in place and break up
the surface, induction and breaks). It
could aim to have up to six net working
hours with an excavation rate to expose
the service of 2.50 m3 per hour.
“Dyno Class” is the 26t/32t truck mounted has a
spoil capacity of between 4.5m3 to 12m3.
Considered nine hours shift and including the
downtime to set up the plant (positioning in place
and break up the surface, induction and breaks). It
could aim to have up to six net working hours with an
excavation rate to expose the service of 4.15m3 per
hour.
City
Rigs
Dyno
Class
(Pier-uk, 2020)
Vacuum Excavation
7. Geotechnical/ground
conditions:
Vacuum
Excavation
*based upon 9 hour shift (incl. downtime** 6.5 working hours). Based upon City Rig Vacuum Excavator.
** Downtime includes and account for: 1 hour break, two breaks of 15 minutes, 30 minutes of induction and 30 extra
additional time of non productive works related activities. Other Non productive time or stand by time incurred for
obstruction or third party delays are not considered and not accounted in the above calculation.
Material
m
3
/hour
(average)
Time for 1m
3
(minutes)
m
3
/ day*
heavy soil with buried cables and pipes 1.65 36 17.875
dry heavy soil 2.5 24 40.625
wet heavy soil or clay 3 20 58.5
moderately heavy soil with buried cables and pipes 4 15 104
muddy soil, gravel, crushed rock 6 10 234
sandy soil 10 6 650
heavy soil with buried cables and pipes excavated by hand 0.35 60 2.275
8. Cost
: • Mobilisation and demobilisation of Vacuum Excavators with two operator
costs up £1,200.00 (min one day for all the type ofVacuum Excavators).
• Average cost for an excavation based upon City Rigs or Dyno class are
around £45,00 per m3.
• Remote towed nozzle or mini-series of Vacuum Excavators has an average
cost for an excavation around £58,00 per m3.
Vacuum Excavation
9. Conclusion:
There are up to 60,000 minor service strikes every year (Ref.:
National Joint Utility Group 2019 - NJUG), with an average direct
cost of £7,000 per strike (Ref.: USAG) plus £29,000 indirect cost
as per every £1,000 of direct cost. According to “report Digging
up Britain”, over the last year there were four million excavations
taking place, which 316,922 of them were urgent or classified as
reactive emergency.
There have been 3,972 injuries (Ref.: HSE 2019 Accident report),
including fatalities, caused by asset strikes. However, note this is
only the number reported to the HSE, it does not include
incidents that were ignored or unreported. USAG report of
accident (voluntary and only from associated members – 34 in
total with a number of over 3,000 severe utilities strike).
Vacuum Excavation advanced technology provides precision
excavation, with complete control thanks to the remote-
controlled excavation arm, also nozzle can be used safely around
any sort of gas pipes (LP/HP). The precision, no-dig approach,
eliminates almost all risk regarding strikes to the service lines
lines (if disconnected by DNO).
Vacuum Excavation
(lmdvacuumexcavation, n.d.)
