Galvanized pipes

Posted in Production range

General

Pre-insulated system of galvanized steel tubes for the underground or above ground hot tap and drinking water is modular, consisting of straight pipes, fittings and closing valves. Each building component (pipe, fitting), is composed of carrier galvanized steel pipe (DIN 2444), the thermal insulation of CFC-free polyurethane foam and protective HDPE (or Spiro) casing tube. Bonded system design prevents relative movement of the steel tube, insulation and casing tube. Line can be equipped with a monitoring system to monitor possible intrusion of moisture into the insulation. Pre-insulated piping system conform to EN 253

Pipe construction
 
Carrier pipe

Galvanized pipe DN 15 - 100 (diameter 1/2” - 4”):

Size   DN 2440, 2441/STN 425710, 425711
Galvanized pipe              DIN 2444
Material   DIN 17100, St 33.0/STN 11343.0
 
Insulation  PUR - foam: according to EN 253, max. operational temperature 110°C
Casing pipe HDPE for aboveground, diameter 90÷250 mm: according to EN 253 , SPIRO for underground
Ends of the pipe  uninsulated end:150 ± 20 mm
 
 

Production range
 
Lengths
 
L = 6000±50 mm
Insulation thickness:
  
 3 insulation series
Casing pipe
 
HDPE - underground 
SPIRO - aboveground
Leak detection:
 
on request
  
 
 
 

d – outer diameter of galvanized steel pipe

D – outer diameter of jacket (t – wall thickness)

L – steel pipe length
 
 
Basic insulation

 DN


Galvanized pipe
 D x t 
 [mm]
casing HDPEpipe
 D 
 [mm]
weight 
 [ kg/m´]
15
1/2”
21,3 x 2,65
90
2,7
20
3/4”
26,9 x 2,65
90
3,0
25
1”
33,7 x 2,95
90
3,8
32
1 1/4”
42,4 x 2,95
110
4
40
1 1/2”
48,3 x 2,95
110
4,0
50
2”
60,3 x 3,25
125
6,0
65
2 1/2”
76,1 x 3,25
140
8,0
80
3”
88,9 x 3,65
160
10,0
100
4”
114,3 x 4,05
200
15,0
 

Stronger insulations (B and C insulation class) can be delivered as well. Other wall thickness of carrier pipes can be delivered on request. Joints insulation is identical as for standard steel production range. 

 

Compensation of thermal pipe extension, method of deposition


When temperature changes pipeline length is changed according to equation:

Δlx = l . α . Δt   

α – coefficient of linear expansion

ΔT – temperature difference installation and operation

L – length messured


The length change is also influenced by friction force depending on the backfill and diameter of casing pipe (the range is from  1,3 kN/m to 8 kN/m of the pipe). Basically it is possible to use  2 methods of pre-insulated galvanized steel piping installation.

  •   cold, with the use of compensation
  •   with thermal pre-stress (tprest = 30 ... 35°C) before backfilling of piping line
Cold installation
Lm (izolácia triedy A) [m]
 DN 
 H=0,6m 
 H=1,0m 
 H=1,4m 
15
13
9
7
20
20
12
9
25
29
18
12
32
32
19
14
40
35
21
15
50
43
27
19
65
49
30
21
80
55
33
24
100
56
35
25

The method of installation galvanized steel pre-insulated pipes in cold state recognize that allowable stress in the pipe will be exceeded at Media <70 ° C. Then the distance ( at the depth of H ) between the two compensatory elements must not exceed 2xLm ( Lm - shown in the table ) .

For insulation series B is Lm reduced by 12 % . 

In the case of cold state installation method with a long pipeline without the possibility of changing the direction ( compensation element ) is used axial compensators with or without anchors.

Small changes of direction in the trench can be up to 4 ° adjusted by weld . 


Installation
For a secure connection of galvanized steel pipes is recommended method of company UTP Schweissmaterial, with additional material UTP1 (UTP1 MR) and flux-UTP Flux HLS-B. This method ensures undamaged zinc coating on the pipe and high strength joints (see user manual of this company.