ProtectorFlex® ST pipes

01

01 Description

ProtectorFlex^® ST are three-layer heat-resistant pipes made of a polymer compound with enhanced heat resistance.

Sliding additives are added to the composition of the inner layer to reduce friction during cable pulling. Outer layer – a marker layer for cable line labeling.

Versions

Triple-layer
version
Inner layer: smooth
Main layer: load-bearing
Outer layer: marker
Dual-layer
version
Inner layer: smooth, load-bearing
Outer layer: marker

ProtectorFlex^® ST pipes modifications

ProtectorFlex^® ST-OMP pipes are polymer smooth heat-resistant pipes with a fault-locating option for laying and protecting cable lines up to 500 kV.

years 0 + Long service life
(at least 50 years)

Key advantages

Heat-resistant throughout the entire service life
Comply with the requirements of GOST R 70751-2023
Mechanical strength throughout the entire service life
Butt-welded
Flexible, bends require no fittings or manholes

02

02 Application area

Mechanical protection of high-voltage cable lines

6 ^kV 500 ^kV

Intended for both using as a protective casing when crossing roads and railways, as well as for mechanical protection of high-voltage cable lines of nominal voltage classes up to 500 kV at facilities where there are no requirements for the pipe’s resistance to short circuit inside the cable. Any known methods of arranging suits (horizontal directional drilling, puncturing, open-trench laying, etc.).

Laying methods

Horizontal directional drilling (HDD)
Pipe jacking
Open-cut installation

Approved by the Ministry of Construction of the Russian Federation

Included in the State Estimate Standards by the Ministry of Construction of the Russian Federation: Federal cost estimates for materials used in construction.
(Order No. 899/pr dated December 11, 2015).

Included in the Cost Estimate Standards Database

Included in the TSN-2001 Cost Estimate Standards Database, resource codes: 1.12-5-2437 to 1.12-5-2507 (pursuant to Order No. МКЭ-ОД/26-24 dated March 25, 2026).

Included in the Construction Resources Classifier (CRC), resource codes:
24.4.01.03-0001 to 24.4.01.03-0006,
24.4.01.03-0019 to 24.4.01.03-0025,
24.4.01.03-0033 to 24.4.01.03-0039,
24.4.01.03-0047 to 24.4.01.03-0053,
24.4.01.03-0800 to 24.4.01.03-0806.

Approved by Rosseti PJSC

ProtectorFlex^® pipes comply with the technical requirements of Rosseti PJSC and are recommended for use at the facilities owned by Rosseti PJSC and its subsidiaries.

Certified according to GOST R 70751-2023

ProtectorFlex^® pipes are certified under the requirements of GOST R 70751-2023.

03

03 Product range of ProtectorFlex^® ST pipes

Pipe outer diameter D, mm	Ring stiffness SN, kN/m²
	12	16	24	32	48	64	96
	Pipe wall thickness e, mm
50	2,5	2,8	3,1	3,4	3,9	4,3	4,8
63	3,2	3,5	4,0	4,3	4,9	5,4	6,1
75	3,8	4,2	4,7	5,2	5,9	6,4	7,2
90	4,6	5,0	5,7	6,2	7,0	7,7	8,7
110	5,6	6,1	6,9	7,6	8,6	9,4	10,6
125	6,3	6,9	7,9	8,6	9,8	10,7	12,0
140	7,1	7,8	8,8	9,6	10,9	11,9	13,5
160	8,1	8,9	10,1	11,0	12,5	13,6	15,4
180	9,1	10,0	11,3	12,4	14,0	15,3	17,3
200	10,1	11,1	12,6	13,8	15,6	17,0	19,3
225	11,4	12,5	14,2	15,5	17,6	19,2	21,7
250	12,7	13,9	15,7	17,2	19,5	21,3	24,1
280	14,2	15,5	17,6	19,3	21,8	23,9	27,0
315	15,9	17,5	19,8	21,7	24,6	26,8	30,4
355	18,0	19,7	22,3	24,4	27,7	30,3	34,2
400	20,2	22,2	25,2	27,5	31,2	34,1	38,5
450	22,8	24,9	28,3	31,0	35,1	38,3	43,4
500	25,3	27,7	31,5	34,4	39,0	42,6	48,2
560	28,3	31,0	35,3	38,6	43,7	47,7	54,0
630	31,9	34,9	39,7	43,4	49,2	53,7	60,7
710*	35,9	39,4	44,7	48,9	55,4	60,5	68,4
800*	40,5	44,3	50,4	55,1	62,4	68,2	77,1

* Manufactured in accordance with TU 2248-003-34311042-2015.

04

04 Technical specifications of ProtectorFlex^® ST

Indicator	Value
Climatic version and installation category	UHL1 (climatic category: cold/ temperature), M1 (standard vibration and shock resistant)
Mean coefficient of linear thermal expansion at 20–70°С, K^-1	1,8 х 10^-4
Vicat softening point,°С	Minimum 125
Thermal conductivity, W/(m·K)	Minimum 0,5
Tensile yield strength, MPa	Minimum 21
Tensile breaking stress, MPa	Minimum 37
Tensile elastic modulus, MPa	Minimum 850
Thermal stability at 200°С, min	Minimum 180
Elongation at break, %	Minimum 350
Insulation resistance*, MOhm	Maximum 0,1
Shore D surface hardness of the pipe	Minimum 58
Resistance to oils, gasoline, groundwater	Resistant
Flame-resistant inner layer	FV-2
Resistance to ignition by a heated wire, °С	850
Change in pipe length after heating, %	Maximum 3
Minimum bending radius at 20°С	Minimum 20D*

* D — is the outer diameter of the pipe.

05

05 Minimum pipe bending radius

As per SP 40-102-2000, the minimum bending radius of the pipe *r_min* can be calculated by the formula

Calculation

Е — modulus of elasticity of the pipe material under tension, MPa

σ — yield strength of the pipe material under tension, MPa

D — pipe outer diameter, mm

For example, at Е = 850 MPa and σ = 21 MPa the minimum bending radius will be r = 20D.

Installation experience proves that the minimum bending radius of the pipe also depends on the ambient temperature at the time of pipe laying.

The final recommendations are presented in the table.

Minimum allowable bending radius of the pipe depending on the ambient temperature
Ambient temperature	0°С	10°С	20°С
Minimum allowable bending radius	50D	35D	20D

06

06 Standart
documentation

TU 2248-003-34311042-2015
GOST R 70751-2023

07

07 Example wording for categories
or technical specifications:

Pipe Item name

PROTECTORFLEX Trade name

ST Pipe design

-

OMP Fault-locating modification

(

III Quantity of layers

) —

160 Nominal outer diameter

/

11,0 Nominal wall thickness

SN32 Nominal ring stiffness

F110 Maximum pulling tension

T105 Long-term allowable heating temperature of conductor core

/

1 Technological generation

/

GOST R 70751 Reference number of the manufacturing standart

/

TU 2248-003-34311042-2015 Technical specification reference number

PROTECTORFLEX ST (III) pipe - 160/11,0 SN32 F110 T105 GOST R 70751 / ТU 2248-003-34311042-2015
Polymer smooth heat-resistant pipe for laying and protecting cable lines up to 500 kV
PROTECTORFLEX ST-OMP (III) pipe - 160/11,0 SN32 F110 T105 /1/ GOST R 70751 / TU 2248-003-34311042-2015
Polymer smooth heat-resistant pipe with a fault-locating option for laying and protecting cable lines up to 500 kV

08

08 Main
characteristics

Operating temperature

Long-term allowable heating temperature of cable cores to 105°C
Minimum permissible operating temperature is -70°C
In overload mode of cable lines up to 120°C (for 8 hours a day)
In short-circuit mode up to 250°C on the cable core and 350°C on the cable screen

Shipping length

Standard shipping length is a straight section 13 m (12 m) long or coils of agreed length for pipe diameters up to 110 mm.

09

09 Accessories

ProtectorFlex^® VZK funnels

Polymer, heat-resistant

To prevent cable sheath damage during pulling into pipes

ProtectorFlex^® ZUP protective cable caps

Polymer, watertight

For sealing the ends of backup and operational protective cable pipes

ProtectorFlex^® UVK cable seals

Polymer, watertight, heat-resistant, one-phase

For sealing the space between the cable and the pipe

ProtectorFlex^® UVK-3 cable seals

Polymer, watertight, heat-resistant, three-phase

For sealing the space between 3 cables and the pipe

Electrofusion couplers

Watertight

For welding polymer smooth-walled pipes to each other

ProtectorFlex^® TAP transition adapters

Polymer, heat-resistant

For watertight connection of different types of pipes to each other

ProtectorLine^® KT spacers

Polymer, for all types of pipes

For fixing pipes when installing duct banks