Silane cross-linked polyethylene pipe INTERSOL ... - Watts Industries

Silane cross-linked polyethylene
pipe INTERSOL PEX-b
Main characteristics
Use of INTERSOL ®
PEX-b offers the
following advantages:
• Resistance to electrochemical and chemical
corrosion
• Long life in relation to temperature and pressure
• Resistance to chemicals
• Resistance to high temperature peaks
(up to 110°C)
• Low noise level
• Resistance to plastic creep
• Low pressure drop
• Low formation of deposits
• Resistance to low temperatures
• Flexibility
A Division of Watts Water Technologies Inc.

SILANE CROSS-LINKED POLYETHYLENE PIPE
2
Piping of the INTERSOL ® PEX-b series is made from cross-linked polyethylene, available in versions with or
without oxygen diffusion barrier, and suitable for pipes used for supplying the heat carrier fluid in
heating/plumbing systems.
TPR
INTERSOL ®
Cross-linked polyethylene pipe. Can be used as a viable alternative to
conventional piping (copper - steel - iron). Suitable for heating and plumbing
systems as it is non toxic.
Easy to install. Low pressure drops. Age and corrosion resistant.
Max. temperature: 100 °C.
Conforms with UNI 9338. Approved according to UNI 315 IIP no. 206.
Type Part number Dimensions
TPR 1001112 12 x 2,0
TPR 1001115 15 x 2,5
TPR 1001118 18 x 2,5
TPR 1001120 20 x 2,0
TPR 1001122 22 x 3,0
TPR 1001128 28 x 3,0
TPR 1001132 32 x 3,0
TPRUV
INTERSOL ®
Cross-linked polyethylene pipe resistant to the aging action of UV rays.
Characteristics like TPR, but suitable above all for outdoor sections exposed to
sunlight.
Conforms with UNI 9338. Approved according to UNI 315 IIP no. 206.
Type Part number Dimensions
TPRUV 1001512 12 x 2,0
TPRUV 1001515 15 x 2,5
TPRUV 1001518 18 x 2,5
TPRUV 1001522 22 x 3,0
TPRUV 1001528 28 x 3,0
TPRUV 1001532 32 x 3,0
VPESR
INTERSOL ®
Cross-linked polythene pipe enclosed in corrugated polyethylene sheath.
Characteristics like TPR.
Black sheath.
Conforms with UNI 9338. Approved according to UNI 315 IIP no. 206.
(does not include the sheath).
Type Part number Dimensions
VPESR 1001905 15 x 2,5
VPESR 1001909 18 x 2,5

SILANE CROSS-LINKED POLYETHYLENE PIPE
VPEED
INTERSOL ®
Cross-linked polythene pipe with oxygen diffusion barrier to prevent oxygen
in the air from penetrating inside the water circuit.
Suitable for building radiant panel systems.
Other characteristics like TPR.
3
Conforms with DIN 16892/16898.
Approved according to DIN 4726/4729.
Type Part number Dimensions
VPEED 1001165 16 x 2,0
VPEED 1001166 16 x 2,0
VPEED 1001175 17 x 2,0
VPEED 1001176 17 x 2,0
VPEED 1001185 18 x 2,0
VPEED 1001186 18 x 2,0
VPEED 1001205 20 x 2,0
VPEED 1001206 20 x 2,0
TPRR
INTERSOL ®
Like VPEDD but without the oxygen diffusion barrier.
Conforms with DIN 16892/16893 - UNI 9338.
Type Part number Dimensions
TPRR 1001160 16 x 2,0
TPRR 1001161 16 x 2,0
TPRR 1001170 17 x 2,0
TPRR 1001171 17 x 2,0
TPRR 1001180 18 x 2,0
TPRR 1001181 18 x 2,0
TPRR 1001200 20 x 2,0
TPRR 1001201 20 x 2,0
1 - PLASTICS USED IN HOT /COLD WATER PRESSURE PIPING
INTERSOL ® PEX-b is a cross-linked polyethylene pipe obtained via the silane method, starting from high density
polyethylene. It finds application in the heating and plumbing sector.
In this sector (floor heating, radiator pipe connecting, plumbing systems) it is possible to use the following plastic
materials instead of conventional metal ones:
- Polyethylene (PE)
- Chlorinated polyvinyl chloride (PVC-C)
- Cross-linked polyethylene (PEX)
- Polypropylene random copolymer (PP-R)
- Polybutylene (PB)
Table 1 shows the fields of application of plastics in the pressure pipe sectors.
Table 1
Application PE PVC-C PEX PP-R PB
Domestic cold water Yes Yes Yes Yes Yes
Domestic hot water (60°C) No Yes Yes Yes Yes
Floor heating No No Yes (Yes) Yes
Radiator pipe connecting No No Yes No (Yes)
Legend
Yes = used
(Yes) = used less frequently
No = not used

SILANE CROSS-LINKED POLYETHYLENE PIPE
2 - CROSS-LINKING METHOD
4
High density polyethylene is a thermoplastic macromolecular component, obtained from the polymerization of the
ethylene monomer (CH2 = CH2).
Its chemical formula can be represented as: - (CH2 - CH2) - n
where n defines the length of the macromolecular chain (the average value of n can also lie between
10,000 – 16,000). From now onwards we shall represent such chain as:
Hence polyethylene consists of various macromolecular (polymer) chains, whose cohesion forces cannot strictly
be considered to be true chemical bonds, rather they are electrical in nature and are commonly known as “Van
der Waals” forces. Although such cohesion forces are low, the high number of intramolecular bonds favours
obtaining of certain properties for the product.
However the low energy of the cohesion forces makes the thermoplastic materials highly sensitive to temperature,
which causes considerable decay of the properties.
Suppose in addition to the “Van der Waals” forces, we introduce intramolecular chemical bonds (the so-called
cross-linking bonds), the thermal properties of the product will be considerably improved.
Cross-linking is a process which modifies the chemical structure of the material, by creating a three dimensional
“network” structure thanks to links between the polymer chains. The new structure determines certain special
characteristics, namely:
• an increase in the maximum operating temperature
• a reduction in creep deformation (creep)
• improved chemical resistance
• improved resistance to UV rays
• improved abrasion resistance
• greater impact strength
• less notch sensitivity and abrasion
• thermal memory characteristics are conferred to the material (“thermoelastic polymer”)
2.1 - Classification of the cross-linked polyethylene
Cross-linked polyethylene is classified according to the methods used to perform the cross-linking as summed up
in the following table:
Table 2
Type of cross-linking Cross-linking agent Product symbol
a Chemical Peroxides PEX-a
b Chemical Silanes PEX-b
c Physical Electronic rays (beta) PEX-c
d Chemical Azo compounds PEX-d
Processes a, b and c are the most frequent ones and they will be described in the following pages.
2.2 - Chemical cross-linking with peroxides (PEX-a)
In the Engel method, the peroxide (chemical formula ROOR) is added to polyethylene during the extrusion phase.
The process consists of two steps, namely:
• formation of free radicals
• cross-linking
+ ROOR + ROH
+
Special machines that allow reaching of pressures up to 2000 bar are required to complete such process.

SILANE CROSS-LINKED POLYETHYLENE PIPE
2.3 - Physical cross-linking with radiation, beta rays (PEX-c)
As in the previous situation, likewise here, cross-linking depends on the formation of free radicals, in this case
generated by beta radiation. Such technology is based on the method of cross-linking the finished polyethylene
product by radiating with a high energy electron beam, generated by a particle accelerator. The cross-linking
process can be represented as follows:
5
• formation of free radicals
ray
• cross-linking
+
The processes based on peroxides and radiation generate a bond of the carbon-carbon type between the chains.
2.4 - Chemical cross-linking with silanes INTERSOL ® PEX-b
We shall now go into greater depth as regards the chemical silane cross-linking which, as will be seen below,
creates a carbon-silicon-oxygen-silicon-carbon bond between the chains.
In such process polyethylene is added to a silane, a small quantity of peroxide, acting as an initiator, and an
organometallic catalyst. Cross-linking is performed in two steps: grafting and cross-linking.
Grafting takes place via the extrusion process, which is then followed by cross-linking in water, accelerated by
the catalyst.
The following is a representation of the chemical reaction mechanism with silanes (e.g. vinyl trimethoxysilane
contains a small quantity of dicumyl peroxide):
• grafting
takes place inside the extruder at high temperature (140°C – 190°C)
+ CH2=CH-Si-(OCH3)3
ROOR’
• cross-linking
CH30-Si-OCH3
OCH3
(takes place in contact with water, normally hot between 80°C – 85°C)
+ 3 H2O + 3 CH3OH
CH30-Si-OCH3
OCH3
HO-Si-OH
OH
Cross-linked polyethylene INTERSOL ® PEX-b
condensation
HO-Si-OH
catal.
+ O + H2O
HO-Si-OH
OH
HO-Si-OH
OH
HO-Si-OH
The intramolecular bond that is generated is of the type - Si - HO - Si – possessing an energy comparable to the
- C - C - bond.

SILANE CROSS-LINKED POLYETHYLENE PIPE
3 - MANUFACTURING PROCESSES INVOLVING SILANE CROSS-LINKING
6
The use of silanes as cross-linking agents is based mainly on two industrial methods:
1) A TWO-STEP PROCESS (SIOPLAS)
2) A ONE-STEP PROCESS (MONOSIL)
3.1 - Two-step Sioplas method
The Sioplas method was developed in 1968 and consists of two steps (see figure 2):
-) step 1
Polyethylene, silane and a small quantity of peroxide plus further additives (anti-oxidants) are processed in a
single or twin-screw extruder. They are blended at temperatures such as to “graft” the polyethylene with the
silane. Such cross-linkable product is granulated and stored in air-tight containers.
-) step 2
The cross-linkable polyethylene with the addition of a catalyst masterbatch is melted and reblended in a second
extruder, then converted into the final product (pipe).
These two steps are followed by cross-linking in hot water (normally 80 to 85°C) for a time depending on the pipe
wall thickness.
Diagram of the two-step Sioplas method
Grafting step
Polyethylene+
pellets
Silane+
peroxide
Liquid of
the pump
Step 1
Grafting extrusion
(typically L/D=25)
Pelletizing unit
Shaping step
Ppackaging and
storage in dry
conditions of the
grafted polymer
Grafted pellets
Additives
Anti-oxidant +
Catalyst
Step 2
Shaping
extrusion
Finished product
Cross-linking in water
Fig.2

SILANE CROSS-LINKED POLYETHYLENE PIPE
3.2 - One-step Monosil method
The Monosil method was introduced by Dow Chemical in 1974 and thanks to the development of special
extruders (special screw profiles) by the company Maillefer (see figure 3).
In such process, polyethylene, silane, a small quantity of peroxide, catalyst and further additives are introduced
in a single-screw extruder.
Blending of the products, grafting reactions and formation of the pipe are completed in just one extrusion and
drawing line.
Cross-linking is performed in hot water as in the previous case.
The INTERSOL ® PEX-b pipe is manufactured with the latter technology, starting directly from the raw materials
purchased from manufacturers with consequent advantages of 100% quality control over all the pipe
manufacturing phases as it is not necessary to depend on intermediate manufacturers as would be required by
the Sioplas method.
7
Diagram of the one-step Monosil process
Polyethylene
pellets
Anti-oxidants
Silane+
peroxide+
catalyst
Finished product
Grafting and shaping extrusion
(typically L/D=30)
Cross-linking in water
Fig.3

SILANE CROSS-LINKED POLYETHYLENE PIPE
4 - MANUFACTURING PROCESS AND TESTING OF INTERSOL ® PEX-b
8
Silane + liquid
Anti-oxidant
Non cross-linked
polyethylene
RAW MATERIAL
Testing (organoleptic
melt index, etc.)
EXTRUSION
Anti-diffusion barrier
Process control
(temperature-screw revs., etc.)
FORMING
Inspection (appearance, centering, wall thickness,
O.D., marking)
CROSS-LINKING
Process control
(bath temperature, duration)
FINISHED PRODUCT
Final testing
(degree of cross-linking,
resistance to internal
pressure Vs. temperaturecold
rupture tests,
tensile tests)
INTERSOL-iip 206-UNI-315-PE-X 15x2.5-PN 16 10bar/80°C
Cross-linked
polyethylene
5 - PROPERTIES OF INTERSOL ® PEX-b
Use of INTERSOL ® PEX-b offers various advantages, above all:
1) Resistance to electrochemical and chemical corrosion
2) Long life in relation to temperature and pressure
3) Resistance to elevated temperature peaks (up to 100°C)
4) Resistance to chemicals
5) Low noise level
6) Resistance to plastic creep
7) Low pressure drop
8) Low formation of deposits
9) Resistance to low temperatures
10) Flexibility

SILANE CROSS-LINKED POLYETHYLENE PIPE
5.1 - Technical data of INTERSOL ® PEX-b
Table 3
Mechanical properties Standard Unit Value
Specific gravity DIN 53479 gr/cm 3 0,95
Tensile strength (20°C) DIN 53455 MPa 22 - 27
Elongation at break (20°C) DIN 53455 % 350 - 550
Tensile modulus of elasticity (20°C) DIN 53457 MPa > 550
Impact strength (20°C) DIN 53453 KJ/m 2 No breakage
Moisture absorption (100°C) DIN 53472 % 0,05
Thermal properties
Operating temperature - °C -100 / +100
Softening point - °C 125
Coefficient of linear expansion (20°C) - °C -1 1,4*10 -4
Coefficient of linear expansion (100°C) - °C -1 2,0*10 -4
Impact strength (20°C) - KJ/Kg°C 2,0
Moisture absorption (100°C) DIN 52612 W/m°C 0,35 - 0,41
Electrical properties
Specific internal resistance (20°C) - m 10 15
Dielectric constant (20°C) - - 2,2
Dielectric strength (20°C) - KV/mm 20
9
6 - STANDARD SIZES OF INTERSOL ® PEX-b
Standard pipe dimensions depend on the field of application and typical standards of each nation.
Above all, distinction can be made between two sectors, namely:
-Floor heating and connection of radiators
-Plumbing systems
6.1 - Floor heating and connection of radiators
Two types of pipe can be used, namely:
a) with oxygen diffusion barrier, consisting of a film of coextruded ethylene vinyl alcohol (EVOH)
Table 4
O.D. - for wall thickness Typical Countries Weight (Kg/m) Capacity (l/m)
14 x 2 DD Germany 0,083 0,074
16 x 2 DD Italy 0,097 0,109
17 x 2 DD Germany 0,102 0,126
18 x 2 DD Italy 0,109 0,148
20 x 2 DD Italy - Germany 0,122 0,193
Standard length: 100 - 120 - 200 - 240 metres
b) without anti-oxygen barrier
Table 5
O.D. - for wall thickness Typical Countries Weight (Kg/m) Capacity (l/m)
12 x 2 Italy 0,065 0,048
16 x 2 Italy 0,092 0,108
18 x 2 Italy 0,104 0,150
20 x 2 Italy 0,119 0,194
12 x 1,1 France 0,042 0,073
16 x 1,5 France 0,072 0,128
20 x 1,9 France 0,112 0,201
25 x 2,3 France 0,167 0,318
Standard length: 100 - 120 - 200 - 240 metres

SILANE CROSS-LINKED POLYETHYLENE PIPE
6.2 - Plumbing systems
10
Table 6
Dimensions - For wall thickness Typical Countries Weight (Kg/m) Capacity (l/m)
12 x 2 Italy 0,065 0,048
15 x 2,5 Italy 0,100 0,076
18 x 2,5 Italy 0,124 0,127
22 x 3 Italy 0,181 0,193
28 x 3 Italy 0,231 0,376
32 x 3 Italy 0,274 0,521
16 x 2,2 Germany 0,098 0,102
20 x 2,8 Germany 0,153 0,156
25 x 3,5 Germany 0,233 0,251
32 x 4,4 Germany 0,382 0,410
12 x 1,1 France 0,042 0,073
16 x 1,5 France 0,072 0,128
20 x 1,9 France 0,112 0,201
25 x 2,3 France 0,167 0,318
Standard length: 50 - 75 - 100 metres
7 - STANDARDS AND RECOMMENDATIONS
Table 7
GERMANY
STANDARD
Heating
system
Plumbing
system
DIN 16892 Pipes made from high density, cross-linked polyethylene (VPE), X X
general requirements, testing.
DIN 16893 Pipes made from cross-linked polyethylene (VPE), dimensions. X X
DIN 4726 Plastic pipes used in hot water floor heating systems, X
general requirements.
DIN 4729 (*) High density, cross-linked polyethylene pipes for use in hot water floor X
heating systems, general requirements and testing
DIN 4725 Hot water floor heating systems; X
thermal tests (design)
DIN 8076/1 Fittings for floor heating systems X
DIN 1988 + KTW Code of practice for drinking water supply systems X
DVGW - W531 Manufacture, safety and testing of cross-linked polyethylene pipes
(HDPE) for drinking water in home installations
X
DVGW - W532 Metal fittings for cross-linked polyethylene pipes (HPDE)
used in drinking water installations
X
(*) related to and cited in DIN 4726.
Table 8
ITALY
STANDARD
Heating
system
Plumbing
system
UNI 9338 High density, cross-linked polyethylene pipes (VPE), X X
general requirements, testing.
UNI 9349 Cross-linked polyethylene pipes (VPE), dimensions. X X
Recommendation Plastic pipes used in hot water floor heating systems, X X
IIP n°16
general requirements.

SILANE CROSS-LINKED POLYETHYLENE PIPE
Table 9
FRANCE
STANDARD
Heating
system
Plumbing
system
11
NFT 54-085 Cross-linked polyethylene pipes (PEX) for transport of fluids under X X
pressure; requirements
NFT 54-026 Thermoplastic pipes used for transport of fluids; X X
determination of tensile properties.
NFT 54-021 Thermoplastic pipes used for transport of fluids; X X
determination of longitudinal shrinkage Vs. increase in temperature
NFT 54-025 Thermoplastic pipes used for transport of fluids; determination of X X
pressure resistance at constant temperature
8 - FACTORY TESTS CONDUCTED ON INTERSOL ® PEX-b
Table 10
TEST STANDARD MAIN REQUIREMENTS
Dimensional checking UNI 9338 O.D. - 0
DIN 16893 +0,3
NFT 54-085 Wall thickness - 0
+0,3
Degree of cross-linking UNI 9338 > 65%
DIN 16892
Thermoxidation UNI 9338 No surface alteration
DVGW-W531
Pressure resistance at constant temperature UNI 9338 Temperature = 95°C
DIN 16892 Stress = 4,8MPa time ≥ 1h
NFT 54-085 Stress = 4,7MPa time ≥ 170h
Stress = 4,4MPa time ≥ 1000h
Cold rupture test
Tensile properties NFT 54-026 Yield stress ≥ 20 MPa
Stress to rupture
20 MPa
Elongation at break ≥ 20 MPa
Linear shrinkage Vs. increase in temperature NFT 54-021 Shrinkage 2,5 %
(120°C - 1h)
Microstructural analysis UNI 4729
DVGW-W531
9 - LONG-TERM PROPERTIES OF INTERSOL ® PEX-b
For determination of permissible stress levels in long-term operation, the mechanical behaviour of the pipe was
evaluated experimentally (minimum resistances) by submitting it to pressure at different temperatures for long
periods of time. The regression curves of the INTERSOL ® PEX-b pipe at various temperatures (see figure) were
derived from these tests. In the case of very long times, resistances were calculated by extrapolation.
For a pipe under pressure the equivalent stress generated by the internal pressure is calculated using the
following formula:
e =
P x (de - s)
20 x s
where e is the equivalent stress in N/mm 2
P is the pressure in bar
de is the outer diameter of the pipe in mm
s is the wall thickness of the pipe in mm

SILANE CROSS-LINKED POLYETHYLENE PIPE
We shall show an example of calculating the factor of safety :
12
Suppose we have a pipe with dimensions 16 x 2 - Max. operating pressure = 3 bar
Max. operating temperature = 70°C - Required duration = 50 years
On the basis of the above data, we can deduce the equivalent force:
e =
P x (de - s)
20 x s
=
3 x (16 - 2)
20 x 2
= 1,05 N mm 2
from the regression curve at 70°C it can be seen that max. stress for the period of 50 years is equal to:
max = 5,4 N/mm 2
hence the factor of safety is as follows:
fs = max
e
= 5,4 = 5,1
1,05
For example, in accordance with UNI 9338 standard, two classes of nominal pressure are defined (max. permissible
pressure for continuous duty with water at 20°C), namely PN10 and PN16, depending on the dimensions, as given
table 11. Therefore having defined a factor of safety equal to 1.3, table 12 shows the safety operating pressures for
different temperature and time ranges.
Table 11 Table 12
Nominal
O.D.
Average
O.D.
Wall thickness
PN 10 PN 16
10 10 +0,3 - 1,8 +0,1
12 12 +0,3 - 2,0 +0,2
14 14 +0,3 - 2,0 +0,2
15 15 +0,3 2,0 +0,2 2,5 +0,2
16 16 +0,3 2,0 +0,2 2,5 +0,2
17 17 +0,3 2,0 +0,2 2,3 +0,2
18 18 +0,3 2,0 +0,2 2,5 +0,2
20 20 +0,3 2,0 +0,2 2,8 +0,2
22 22 +0,3 2,0 +0,2 3,0 +0,3
25 25 +0,3 2,3 +0,2 3,5 +0,3
28 28 +0,3 3,0 +0,3 4,0 +0,3
32 32 +0,3 3,0 +0,3 4,4 +0,4
Temperature (°C) Factor Duration Max.permissible Max. permissible
of safety (years) safety force operating pressure
(MPa)
(bar)
PN 10 PN 16
up to 60°C 1,3 50 5,0 10 16
over 60°C
up to 80°C
1,3 50 3,8 6 10
over 80°C
up to 95°C
1,3 10 3,2 6 10

SILANE CROSS-LINKED POLYETHYLENE PIPE
REGRESSION CURVE
13
10
20 °C
30 °C
40 °C
Hydrostatic stress (MPa)
50 °C
60 °C
70 °C
80 °C
90 °C
95 °C
110 °C
0
0,1
1,0 10,0 100,0 1000,0 10000,0 100000,0 1000000,0
Time to fracture (h)
50 years

SILANE CROSS-LINKED POLYETHYLENE PIPE
10 - LINEAR THERMAL EXPANSION OF INTERSOL ® PEX-b
The variation in pipe length against rise in temperature can be calculated using the following formula:
14
ΔL = ∂ x L x ΔT
where
ΔL = variation in length (mm)
ΔT = variation in temperature (°C)
L = pipe length (m)
∂ = coefficient of linear expansion = (average value 1,8 x 10 -4 )
Example:
ΔT = 50°C
L = 6 m
ΔL = 54 mm
(see graph)
180
Linear expansion Vs. increase in temperature
10
160
140
Pipe lenght (m)
9
8
7
Variation in lenght (mm)
120
100
80
60
6
5
4
3
40
2
20
1
0
0 20 40 60 80 100
Variation in temperature (°C)

SILANE CROSS-LINKED POLYETHYLENE PIPE
11 - OTHER PROPERTIES OF INTERSOL ® PEX-b
11.1 - Two-step Sioplas method
Thanks to its flexibility, INTERSOL ® PEX-b can be “cold” bent up to bend radii equal to 5 times the outer diameter.
For smaller bend radii, it is necessary to heat the pipe using hot air at 130 – 150°C (never use a direct flame).
15
Table 13
Outer diameter Cold bending Hot bending
12 60 27
14 70 31
15 75 34
16 80 36
17 85 38
18 90 40
20 100 45
25 125 56
11.2 Behaviour on exposure to light
INTERSOL ® PEX-b should be stored and installed away from direct exposure to sunlight. The UV rays would
cause aging of the material, thus impairing the chemical-physical and mechanical properties.
11.3 Behaviour at low temperature
The water contained in the pipe must not freeze because the variation in phase would cause an increase in
volume with risk of the pipe caving in.
Anti-freeze substances can be used for applications below 0°C.
11.4 Pressure drop
The advantage of INTERSOL ® PEX-b is that it has an internal surface free from roughness. Therefore it will
remain free from encrustations during the years of service and with very low coefficient of friction. The pressure
drops for transport of water at 20°C are given in the following graph where the correction factors associated with
the different water temperatures are given. N.B. where anti-freeze substances are present, due account should
be taken of the variation in viscosity of such solutions.
10000
Pressure drop per metre of pipe (Water temperature = 20°C)
Conversion temperatures for other temperatures: 30°C=0,95 40°C=0,92 50°C=0,88 60°C=0,85 80°C=0,82
Pressure drop/metre (mm CA/m)
1000
100
10
1
8
10
Inner diameter (mm)
12 13 14
16
18
20
22 24 26 0,1 m/s
0,2 m/s
0,3 m/s
1,0 m/s
0,9 m/s
0,8 m/s
0,7 m/s
0,6 m/s
0,5 m/s
0,4 m/s
4,0 m/s
3,5 m/s
3,0 m/s
2,5 m/s
2,0 m/s
1,5 m/s
0,1
10 100 1000 10000
Flow rate (lt/h)

SILANE CROSS-LINKED POLYETHYLENE PIPE
11.5 Behaviour to chemical agents
16
Cross-linked polyethylene exhibits good resistance to chemical agents. The following table shows the behaviour
of INTERSOL ® PEX-b in relation to the substance and temperature where there is no external stress.
SUBSTANCE 20°C 60°C SUBSTANCE 20°C 60°C SUBSTANCE
20°C 60°C
acetic acid 10% formaldehyde 40% polyglycols
acetone formic acid potassium chloride (wat. sol.)
acrylonitrile frigene potassium dichromate 40%
aliphatic esters fuel oil potassium hydroxide 30%
allyl alcohol glycerine propanol
aluminium sulphate (wat.sol.) glycol propionic acid 50%
ammonia (wat. sol.) hexane propyl alcohol
ammonium sulphate (wat.sol.) hydrofluoric acid 70% pure aniline
aromatic esters hydrogen peroxide 30% pyridine
beer hydrogen peroxide 100% silicone oil
benzene hydrogen sulphide sodium hydroxide
benzoic acid (wat. sol.) linseed oil sodium hypochloride
bitumen liquid soap sulphur trioxide
bleach liquor magnesium salts (wat.sol.) sulphuric acid 50%
bromium maleic acid sulphuric acid 98%
butanol mercury synthetic detergents
butter methanol tetrahydrofuran
butyl acetate methyl ethyl ketone tetralin
butyne diol methyl phenol tincture of iodine
butyric acid methylene chloride toluene
carbon dioxide milk transformer oil
carbon tetrachloride motor lubricants trichloroethylene
chloroform naphtha turpentine
chromic acid 50% naphthalene vaseline
citric acid nitric acid 30% vegetable oils
conc. hydrochloric acid nitric acid 50% washing detergents
cyclanone nitrobenzene water
cyclohexanol oleum wine
cyclohexanone oxalic acid 50% xylene
decalin
ozone
dibutyl phthalate
paraffin oil
dichlorobenzene
petrol
dichloroethylene
petroleum
diesel oil
petroleum ether
diethyl ether
phenol
ethyl acetate
phosphates (water.sol.)
ethyl alcohol phosphoric acid 95%
ethylene glycol phthalic acid 50%
Legend :
Resistant Fairly resistant Non resistant

SILANE CROSS-LINKED POLYETHYLENE PIPE
12 - APPROVALS FOR INTERSOL ® PEX-b
As the pipe manufacturing system is certified to ISO 9002, there are certain receiving, in-process and final
test/inspection procedures, as already mentioned previously. Consequently all INTERSOL ® PEX-b pipes are
submitted to in-house final testing, in accordance with the requirements of European standards in the sector,
which differ according to the country of destination (e.g. UNI 9338/9349, DIN 16892/16893, DIN 4726/4729, UNE
53-381-89/53-023-86-53133-82, see previous table). Furthermore there are various product certifications,
entrusted to officially recognized testing body which can be summed up as follows:
17
Table 15
Country Approval Body Floor heating Plumbing Main captions
ITALY I I P – Istituto Italiano Plastici X X UNI 315 IIP 206
GERMANY SKZ X X DIN GEPRUEFT
Süddeutsche (only chemical (only chemical DIN 4726
Kunstoff Zentrum physical tests) physical tests) DIN 16892
DIN 4726
DIN 16892
GERMANY DVGW - Igiene Institut X DVGW
(migration) DW 8306 AL 2002
GERMANY MPA - NRW X Diffusionsdicht
Materialprufungsamt
(oxygen
Nord-RheinWstfalen
diffusion)
FRANCE C.S.T.B. Centre Scientifique et X X
Technique du Batiment
PORTUGAL LNCE National Civil Engineering X X
Laboratory
HUNGARY EMI - TÜV X X
Hungarian Section of German TÜV
SPAIN AENOR Spanish Standards Institute X X
U.S.A. NSF International X X Standard 14
Body Certification
product standard
ASTM F876-877,
included chlorine,
CSA 137.5.
Standard 61
13 - COMPARISON OF DFFERENT PLASTICS USED IN HOT WATER PIPING
Table 16 shows different behaviours of cross-linked polyethylene (PEX), polybutylene (PB) and polypropylene
random copolymer (PP/R) materials with reference to certain important properties for applications in the heating
and plumbing industries.
Table 16
Property PEX PP-R PN
Stability in hot water (95°C) A C B
Long-term behaviour (up to 95°C) A C B
Flexibility A B A
Impact strength (also at low temperatures) A C B
Elongation (longitudinal tensile test) C B C
Toxicity A A A
Creep properties A C B
Thermal conductivity B B B
Surface A A A
A = very good B = good C = sufficient

SILANE CROSS-LINKED POLYETHYLENE PIPE
Table 17 is compiled from literature data and gives a detailed survey of typical values for certain characteristics
compared to those of INTERSOL ® PEX-b
18
Table 17
Property Standard Unit PEX-a INTERSOL ® PEX-b PEX-c PP-R PB
Specific gravity DIN 53479 G/cm 3 0,94 0,95 0,94 0,90 0,93
Ultimate tensile strength DIN 53455 N/mm 2 26-30 22-27 22-25 40 33
Elongation DIN 53455 % 350-550 350-550 350-450 800 300
Tensile modulus of elasticity
(20°) DIN 53457 N/mm 2 >550 >550 >550 >800 >350
Coefficient of linear expansion
(20°C) - °C 1,4.10-4 1,4.10-4 1,4.10-4 1,5.10-4 1,5.10-4
Thermal conductivity - °C 2,0.10-4 2,0.10-4 2,0.10-4 - -
Coefficient of linear expansion
(20-100°C) - W/mk 0,38 0,35-0,41 0,35 0,24 0,23
Degree of cross-linking DIN 16892 % >75 >65 >60 - -
The descriptions and photographs contained in this product specification sheet are supplied by way of information only and are not binding.
Watts Industries reserves the right to carry out any technical and design improvements to its products without prior notice.

SILANE CROSS-LINKED POLYETHYLENE PIPE
WARRANTY FOR CROSS-LINKED POLYETHYLENE (PEX)
PIPE FOR HOT FLUID PRESSURE PIPING
19
TUBO INTERSOL ®
The pipe is produced within a certified quality management system in accordance with UNI EN
ISO 9001:2000. The INTERSOL ® pipe is produced using top quality raw materials and a high
technology production cycle.
Product quality is guaranteed by strict control plans in every phase of the transformation, from
the raw materials to the process to the finished product. In addition, all coils produced are
subject to a final hydraulic test.
The specific tests for the INTERSOL ® , pipe, performed in-house, comply with sector
regulations that vary based on the country for which the pipe is intended (for example UNI
9338/9349 - DIN 16892/16893 - DIN 4726/4729 - NFT 54085 - UNE 53381).
As a result, Watts Industries Italia S.r.l. warrants the INTERSOL ® pipe as indicated below :
1) INTERSOL ® pipes will be replaced free of charge up to 10 years after the date of supply if
damage is caused by manufacturing defects (note: “Manufacturer's warranty provided
based on technical experience in product obsolescence”)
2) damage to third parties due to manufacturing defects in the INTERSOL ® pipe based on
current provisions of law (Presidential Decree 224 of May 24, 1988), will be indemnified
through insurance coverage pursuant to product liability policy VO 100008604 from
Winterthur Assicurazioni.
There is a single maximum coverage per claim per year, of €453,780.00.
Points 1) and 2) above will be valid provided the following conditions are met :
a) The INTERSOL ® dpipe must be stored, handled and installed according to the instructions
reported in our technical specifications
b) Operating conditions (pressure and temperature) must comply with the limits reported in our
technical specifications
c) The product must bear our fully intact identification mark.
The customer must provide the following information when requesting warranty service :
- place and date of installation
- the pipe's identifying data and mark
- information on conditions of pipe installation and operation (temperature and pressure)
- sample on which the breakage occurred (preferably at least 1 meter long with the break in
the middle)
Watts Industries Italia S.r.l. reserves the right to examine the cause of the break on site before
initiating the warranty procedures.
A Division of Watts Water Technologies Inc.

Product range Watts Industries
- System disconnectors
- Backflow protection devices
- Check valves
- Safety units
- Safety relief valves
- Pressure reducing valves
- Automatic control valves
- Butterfly valves
- Shut off valves
- Measuring gauges
- Temperature control
- Expansion vessels
- Process switches
- Fuel products
- Gas products
- Electronic controls
- Installation protection products
- Radiator valves
- System products
- Manifolds and fittings
Re-order no. 90-0005-UK-IT/1-07-06-Rev.0
A Division of Watts Water Technologies Inc.
Watts Industries Italia S.r.l.
Via Brenno, 21 - 20046 Biassono (MI), Italy
Ph. +39 039 49.86.1 - Fax +39 039 49.86.222
e-mail : info@wattsindustries.it - www.wattsindustries.com