Dupont Realshield.qxp (Page 1) - DuPont™ Tyvek

Easy to install
High levels of protection
protection
CI/SfB
October 2006
DuPont Realshield
Gas Barriers
Ln6

Gas protection
Occupants of buildings must be
protected against harm from gases
which occur in the ground and may
seep into the building through
cracks and gaps in the structure,
eventually rising to harmful levels.
Building regulations require
precautions be taken:
‘to avoid danger to health and
safety caused by substances
found on or in the ground to
be covered by the building’
The three gases which constitute
the main threats to health are:
❏ Radon - a naturally occurring
radioactive gas which, over a
long period of time, can induce
lung cancer.
❏ Methane - a flammable
asphyxiating gas which can
occur naturally but is often
given off by landfills.
❏ Carbon dioxide - an asphyxiating
gas, often produced by landfills.
The most effective way to prevent
those gases from reaching the
interior of the building is to install a
continuous gas barrier across the
whole footprint of the building.
The DuPont range of Realshield
Gas Barriers offers you a choice of
high performance barriers which
are easy to install in any type of
building, providing protection for
the occupants.
DuPont Realshield Gas Barrier
Gas rising from ground
Figure 1
2

3
Selecting your DuPont Realshield Gas Barrier
The range of DuPont Realshield Gas Barriers has been engineered to
provide high levels of gas protection to meet the requirements of your
project; use this table to determine which DuPont Realshield Gas Barrier
best suits your needs.
Gas barrier
DuPont
Robustness Radon Methane CO2
Product selector:
Realshield
DPM
Radon 300
A mono-layer of blown
PE film, 300 microns thick.
✔ ✔ ✔ ✔
DuPont Realshield
Radon 400
A mono-layer of blown
PE film, 400 microns thick.
DuPont Realshield
Radon Plus
A four-layer gas barrier
consisting of a HDPE core
and polyester reinforcing
grid bonded between two
layers of LLDPE
DuPont Realshield
Total
A six-layer gas barrier,
consisting of aluminium
foil and a reinforcing
polyester grid sandwiched
between four layers of
polyolefins.
✔ ✔ ✔ ✔
✔ ✔ ✔ ✔
✔
✔ ✔ ✔ ✔
Accessories
A full range of accessories is available, contact your local DuPont Realshield
stockist for details.

DuPont Realshield Gas
Barriers
DuPont Realshield Gas Barriers
can be installed:
❏ under a groundbearing slab
(figure 2)
❏ over a groundbearing slab
(figure 3)
❏ over a beam and block floor
(figure 4).
To avoid the risk of gas collecting
under the barrier there must be a
path for it to escape to
atmosphere. This can be a
prefabricated or brick sump
(figure 5) or a geotextile drainage
matting connected to an extract
pipe as discussed in BRE
publication ‘Radon: guidance on
protective measures for dwellings’.
In beam and block floors cross
vents in the supporting walls will
allow the gas to disperse.
brick sump
Figure 5
Figure 2
Figure 3
Figure 4
4

5
Preparation
The surface onto which the barrier
is to be laid must be even, smooth
and free from projections.
Hardcore must be blinded with
25mm of sand, concrete must
have a smooth floated finish.
Laying the barrier
❏ lay the first run of DuPont Realshield.
❏ apply DuPont Tyvek ® Butyl
Tape about 50mm in from the
edge of the first run.
❏ lay the second run of DuPont
Realshield to overlap the first
run by 150mm whilst
progressively removing the
protective cover strip from the
tape. ➀
❏ use a hand roller to press the
top sheet firmly down and
ensure a gas-tight joint. ➁
1
2
Points to watch
DuPont Realshield Gas Barriers
are robust, but care must be
taken to avoid damaging the
barrier both during and after
installation.
Any damaged areas should be
patch repaired using DuPont
Realshield Gas Barrier and Tyvek ®
Butyl Tape.

Wall cavities
Form a continuous gas barrier
across all wall cavities by continuing
the DuPont Realshield Gas Barrier
across the cavity and supporting it
on a lightweight former, or concrete
(figure 6). Alternatively, install a
gas-resistant cavity tray and seal it
to the barrier inside the cavity
(figure 7).
Internal walls
Continue the gas barrier beneath all
internal walls (figure 8). It may be
easier to build the wall on a strip of
gas barrier to which the main areas
of barrier are then sealed. This
method will reduce the risk of
damaging the barrier during
construction.
Penetrations
Keep the number of service
penetrations to a minimum.
Where a penetration is unavoidable,
seal the pipe with a preformed ‘top
hat’ (figure 9):
❏ cut a neat hole in the barrier and
fit it to the penetration
❏ seal and clamp the ‘top hat’ to
the pipe and to the barrier using
Tyvek ® Butyl Tape.
Figure 6
Figure 7
Figure 8
Figure 9
6

7
Technical performance
Test
Radon
permeability 1
(m 2 /s)
Radon
transmittance 1
(m/s)
Methane
permeation
(g/m 2 /24h)
MVTR
(25˚C 75% RH)
(g/m 2 /24h)
Tensile strength
unaged (Mpa)
Tensile strength
heat aged (Mpa)
Tensile strength
UV aged (Mpa)
Elongation
unaged (%)
Elongation
heat aged (%)
Elongation
UV aged (%)
Nail tear
resistance
unaged (N/mm)
Nail tear
resistance heat
aged (N/mm)
Low temp.
flexibility 0˚C
Resistance to
leakage at
joints
Shear at
joints (N)
Method
SP Swedish
National Testing
and Reseach
Institute
SP Swedish
National Testing
and Reseach
Institute
BR 212
BS 31177: 1959
(1995)
IS EN ISO 527-3:
1996
IS EN ISO 527-3:
1996
IS EN ISO 527-3:
1996
IS EN ISO 527-3:
1996
IS EN ISO 527-3:
1996
IS EN ISO 527-3:
1996
MOAT 27: 1983
(5.4.1)
MOAT 27: 1983
(5.4.1)
MOAT 27: 1983
(5.4.2)
MOAT 27: 1983
(5.2.1)
MOAT 27: 1983
(5.2.2)
1 assuming thickness of test specimen 0.000515m
DuPont Realshield
Radon Plus

Physical description
Mean sheet thickness (mm)
Standard roll width (m)
Standard roll length (m)
Standard roll weight (kg)
Colour
Technical performance
Test
Radon
permeability 1
(m 2 /s)
Radon
transmittance 1
(m/s)
Tensile
strength (Mpa)
Method
SP Swedish
National Testing
and Reseach
Institute
SP Swedish
National Testing
and Reseach
Institute
DuPont
Realshield
Radon 300
DuPont
Realshield
Radon 400
0.3
0.4
4
4
25
25
30
40
Green Green
DuPont Realshield
Radon 300
DuPont
Realshield
Radon Plus
0.33
3
16.6; 25; 33
17; 26; 34
Red
6 x 10 -12 8 x 10 -12
20 x 10 -9 19 x 10 -9
DuPont
Realshield
Radon Total
0.413
2
25; 50
22; 44
Black
DuPont Realshield
Radon 400
Long Transverse Long Transverse
22.5 - 25.5
22.0 - 26.0 22.0 - 25.0 21.5 - 25.5
Elongation (%) ISO 1184
550 - 650 600 - 700 550 - 600 600 - 700
Tear resistance
(N/mm)
ISO 1184
ISO 6383/2
25 - 45
1 assuming thickness of test specimen 0.000515m
60 - 100 25 - 45 65 - 100
8

Notes

Notes

Ordering
DuPont Realshield Gas Barriers
and accessories are available from
your local stockist:
DuPont Realshield Gas Barriers
are manufactured by DuPont
under ISO 9001 Quality Assurance
System.
Technical Support
DuPont is happy to provide
technical advice on how best to
incorporate DuPont Realshield
Gas Barrier into various kinds of
construction.
DuPont offers:
❏ technical literature
❏ telephone help line
+352 3666 5885
❏ copies of reports and
certificates
❏ material samples
❏ advice on meeting the
requirements of Building
Regulations and Building
Standards.
Recommendations as to methods, use of materials and construction details are based on the experience and
current knowledge of DuPont and are given in good faith as a general guide to designers, contractors and
manufacturers. This information is not intended to substitute for any testing you may need to conduct to
determine for yourself the suitability of our products for your particular purposes. This information may be
subject to revision as new knowledge and experience becomes available. Since we cannot anticipate all
variations in actual end-use conditions, DuPont makes no warranties and assumes no liability in connection
with any use of this information. Nothing in this publication is to be considered as a licence to operate under
or a recommendation to infringe any patent right.
The DuPont Oval, DuPont , The miracles of science and Tyvek ® DuPont de Nemours (Luxembourg) S.àr.l.
Rue Général Patton
L-2984 Luxembourg
Tel. +352 3666 5885
Fax +352 3666 5021
are trademarks or registered trademarks of
DuPont or its affiliates.
tyvek.construction@lux.dupont.com