Building site systems

VärmeKabelTeknik Building site systems

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Building site systems VärmeKabelTeknik 2

Heating cables on the site

Heating cables are frequently used in a number of different contexts at a building site.

The common denominator for these areas of application is to make construction work possible and easier at the low temperatures occurring in our northern climate.

Example of application areas

Hardening of concrete in foundations, vaults, columns and walls: For hardening at low temperatures as safely and quickly as in summer.

Frost protection of foundations: Eliminates the risk of damage to foundations caused by frost in the underlying ground.

Heating fabrics: Supplementary heat where needed.

Frost protection of water supply and sewer systems: Frost protection of water pipes to barracks and of other temporary water supply and sewer applications.

At Värmekabelteknik we both develop and manufacture products for all existing heating cable applications.

At Värmekabelteknik we have many year´s experience of heating cable applications and are very well aware of the problems which can occur at a building site in cold weather.

Therefore Värmekabelteknik is a reliable and skilled partner for construction work in cold weather.


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Hardening of concrete

The building process is subject to tight schedules. The time of form stripping, for example, is already decided at the design stage, often without taken into consideration the influence of temperature on the hardening time.

For economic reasons, the time available for form stripping is short and stripping must be completed on schedule, in order that no unnecessary delays should occur.

Wall and column forms are normally removed the day after concreting, in practise, after 15‐20 hours. In the case of load‐bearing structures, the formwork is not removed until after a day or so or after about a week, depending on the type of building and type of formwork etc.

The factor that determines the time when the form is to be stripped is the strength of the concrete ‐ not its age. In order for the concrete to become strong enough to allow the form‐work to be stripped, within the scheduled time, extra measures are often required, such as the use of concrete with an accelerated increase in strength, additional heating or insulation.

Cold weather concreting

When casting concrete during the winter period, it will always be necessary to be able to determine its maturation, in order to:

• Avoid strength reduction caused by early freezing.

• Determine the moment when enough strength has been achieved so that the form can be removed. Then, from the point of view of production, there is the possibility of adapting the duration of the cycles so that the set of forms can be used rationally.

Hardening of concrete - a quest ion of temperature

The temperature of the concrete during the time immediately after the concreting affects, in decisive way, the time it takes for the concrete to harden.

A high concrete temperature means fast hardening and, consequently, a low concrete temperature will result in a slower hardening.

A simple and reliable method to keep a high concrete temperature even during cold periods and as a result get quick hardening and early form stripping, is to supply heat by using heating cables.

As a rule, it will be necessary to cover the concrete in order that no part of it should be damaged by frost due to early freezing. Freezing of new concrete causes hardening to stop and results in loss of strength. If freezing occurs too early it may even cause the collapse of a concrete construction.

Increased heat loss in the outer edges of the construction.

.


Supplementary heat in vaults and foundations

Hardening of concrete

With heating cable installed directly in the concrete, any damage and delay due to low temperatures will be eliminated.

The concrete hardens evenly and fast, the forms can be removed after 24 hours and painting can start considerably earlier.

By measuring the temperature in the concrete and controlling the power to the heating cable, the process of hardening can be controlled in order for the concrete to achieve the maximum strength.

With its low running charges and easy installation this is an extremely effective way of saving and a good insurance against the impact of winter on constructions strength and against waste of time. An insurance well worth its price.

Drying-out, heating:

After casting, the heating cables can be used as a source of heat to get a quick drying‐out and to keep the construction warm.

Standard loops:

The heating cable loops are made from TSF‐cable which is designed for this purpose. They are supplied in two different standard lengths, 40 and 95 metres respectively.

The loops are delivered as double‐coiled loops with connecting devices (CEE) fitted.

Length Cable Power Voltage Part.no

40 m TSF 1.0 1325 W 230 V 8987111

95 m TSF 0.17 3275 W 230 V 89871 12 From the table below one can easily find how large a surface each loop will cover for a required output (Watt/m2).

Thereafter you calculate how many loops needed.

Normal output: 120 watt/m2.

Required power

C/C‐Distance (cm) Covered surf. (m²)

40 m 95 m 40 m 95 m

150 20 21 8 20

120 25 26 10 25

90 32 35 13 33

75 40 42 16 40


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Voltage feed

For voltage feed use our distributing TSF‐boxes which are provided with lead‐in devices 4 x 16A + J (3m connection cable) and 3 connecting devices 2 x 16A + J for three heating cable loops (3m connection cables).

The distributing boxes are available in two different designs with or without a thermostat.

Laying out of TSF-cables:

• Fix the connecting device so that the splice between the cold‐lead‐in cable and the heating cable lies in the concrete.

• Unroll and lay the cable to required c/c‐distance.

• Carefully attach the cable to the armouring using a plastic binder, tape or strips.

• Do not let the cable cross itself, a loop must nowhere be laid with a c/c‐distance of less than 6cm.

• Connect the loops to the distribution box and switch on power for a moment in order to check the loops.

Casting:

• In order not to damage the cable and thereby jeopardize the result, it is important to be careful with the cable when the concrete is laid, so that the cable is not trodden on or worn away by tremblers or other tools.

Connection of the cables:

• Connect each loop to the TSF‐boxes.

• Connect the TSF‐boxes to the power service head at the construction site.

• Test the loops by switch on the current a couple of seconds so that you can read the light emitting diode module. PLEASE NOTE! The loops must no be connected more than 30 seconds before casting!

• Apply the concrete, cover with concrete fabric, connect the current. Normally 3 to 5 days are required to obtain necessary strength to the concrete.

Drying-out:

We recommend that a connection box with thermosat is used to avoid overtemperature with cracks as result. The sensor of the thermostat shall be put in a VP‐pipe (16mm) casted in the concrete which are to be heated. This gives an effective heat from inside the concrete vault over the whole surface, which quickly and effectively drives out any moisture.

• Painting can start earlier. • Any future problems with moisture and mould

will be prevented.

Type Content Part.number

TSF‐U Earth‐leakage‐circuit breaker, Power supply indication 89 871 15

TSF‐M Eart‐leakage‐circuit breaker, Power supply indication, thermostat89 871 16


Supplementary heat for wall and column forms

The heater consists of a junction box with an earth‐leakage‐circuit breaker (a requirement even for temporary installations), pilot lamp, main cables with plug (10 A) and, as standard, 4 heating cables with a length of three metres (90 Watt) each.

Heating cables in other lengths are available on request.

Method: Cast the necessary number of VP‐20 pipes in the concrete.

Important! The pipes must be plugged at both ends when casting, so that no concrete can enter.

The heating cables are inserted into the pipes and the heater is connected to the main (230 V).

When the hardening is completed the heating cables are removed and saved for use at the next casting.

As the heater can be used over and over again, it is very suitable as a stock item, thus reducing costs.

Running charges: At an energy price of 35 öre/kWh a standard heater consumes energy at a cost of Sek 3:‐‐/24h.

Power required:

Columns: A standard heater provides the power required for a normal column.

Walls Northn Sweden South Sweden

Power

C/c Power C/c

Form/Construction W/m² Cm W/m² Cm

Plyfa +50 mm cellplast

100

30

75

40

Steele + 50mm cellplast

150

20

100

30

Steele with poor insulation

Plyfa (12mm) non‐insulated

200

15

150

20

Steele, non‐insulated ‐ ‐ 200 15

Wall/Column heater

Symbol Voltage Power Part.no

Wall/Column heater 230 V 4 x 90W 8987025


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Electrically heated wall formwork - type TSV

Electrically heated wall formwork ‐ a step towards simplification and rationalization within the building industry.

The forms are provided with permanently mounted heating cable loops. The heating cable loops constitute a barrier to heat transport from the form, keeping the internal heat of the concrete inside the form so that hardening can go on quickly and effectively.

The desired number of wall forms is connected to an electrical system by means of distributing boxes.

The distributing boxes are equipped with power supply indication and earth‐leakage‐circuit breakers. The earth‐leakage‐circuit breaker is a guarantee of personal safety.

By using an electrically heated wall form the time of hardening can be reduced by between 30 and 60 percent, depending on external conditions such as wind and temperature. The set of forms can be used effectively and so fewer wall forms will be needed.

THE SYSTEM IS WELL TRIED IN FINLAND, AMONG OTHER COUNTRIES, AND SINCE 1988 ALSO IN SWEDEN WITH VERY GOOD RESULTS...

The wall form TSV is suitable for all types of moulding. It is manufactured in 2.5m high and 1m wide form sections of 4mm steel sheets, alternatively 4mm plywood in vertical U‐sections. The forms are combined with horizontal U‐girders to required lengths, from 1 to 6m.

By erecting the formwork using 1m wide elements it is very easy to replace any sections damaged during construction.

Thanks to the horizontal girders the forms will remain straight even after many castings.

The vertical stiffening of the form is achieved through shuttering girders mounted with a c/c‐distance of 1m.

The TSV wall form is constructed in such a way that it is secured with spacers on the upper side and with struts 650mm at the bottom of the form.

For quick and easy formwork erection, standardized and easily mounted details are available, such as brackets, form supports, spacers, end anchorage's, clamp ties, safety chains and struts.


Frost protection of foundations:

Damage to a foundation caused by freezing of the soil under it can easily be eliminated by installing heating cables in the foundation trench.

The heating cables will then work as a barrier of any cold extending downwards.

They cannot, though, be used for thawing of already frozen ground, as the dimensioned output per m² is too low for this purpose.

The installation can, because of its low energy consumption, in most cases remain switched on continuously, but can also be controlled by a thermostat, in which case the sensor is placed just above the layer where the heating cable is laid.

Velox YXR‐loops are made from soft and smooth PVC which makes them easy to handle even at low temperatures.

Velox YXR‐loops are connected only at one end and are reeled out completely.

The standard loops are available in three lengths adapted to the rating of the fuses. The loops are fitted with a 2m cold‐lead‐in cable.

Velox YXR‐lengths:

Length Cable Voltage Power Part.no

(m) (�/m) (V) W.tot W/m

130 0.18 230 2200 17 T13000

230 0.18 400 4040 17 8987223

Important

The cable must not come into contact with any insulation material, for example cellular plastic, mineral wool or the like. It must therefore always be covered with at least 10cm of sand.

Plastic pipes, wires and the like must also be prevented from coming into contact with the heating cable.

Output requirements depend on the depth at which the cable is laid.

The deeper the cable lies, the lower will be the required output.

Installation at a shallow depth can be compensated by a layer of ground insulation.

Example: cable laid at a depth of 15cm plus 5cm ground insulation gives the required output 25 W /m2.

Install. Depth (cm)

Required power (W/m²)

C/C‐Distance (cm)

Min 15 35 60

15 – 20 30 70

20 – 30 25 80

30 – 60 22 90

60 – 80 20 100

80 – 100 17 120

Formula for calculation of cable consumption:

Area (m2) x 100= Cable length m

c/c (cm)


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Installation: Heating cable laid in a bed of sand directly under a layer that will not rise due to frost, eliminates the risk of frost heaving and other types of frost damages.

Pattern No. 1 Single installation. The connection lead is fixed to one edge of the slab and the cable reeled out keeping the c/c‐distance obtained from the table. When the first cable has been completely reeled out, you start again with a new one from the edge, and so on.

Pattern No. 2 Installation of three parallel loops, fed from a three‐phase group. This has the advantage of some output remaining over the whole surface, in case there is a fault on one phase.

Pattern No. 3 Laying so as to get greater heat under the edge beam.


Electric heating fabric

Field of application:

• Thawing (manages approx. 1m depth)

• Thawing of local areas of frozen ground

• Heating of forms

• Frost protection for building sand and other materials sensitive to frost

• Frost protection for pipes and tanks

• Preheating, for example when working with roof applications

Summary: By using an electric heating fabric you supply heat where it is needed.

An electric heating fabric is thin and thus easy to shape.

The electric heating fabric is controlled by a thermostat, which prevents overheating and guarantees a long service life.

HEATING FABRIC Supply voltage 230 Volt.

Symbol Size (m) Heated surface Power (W)

Length Width Lenght Width Total W/m²

Type1100 3.3 1.25 3.2 1.0 1100 344

The electric heating fabric can be delivered in other sizes on request.


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Frost protection for water supply and sewer systems

There are many examples of trouble due to frozen water supply and sewer systems. In addition to the inconvenience caused by out‐of‐order water and discharge pipes, there may be material damages as well that are very expensive and difficult to repair.

An easy method to guard against such problems is to provide frost protection by installing heating cables inside or outside the pipes.

For pipes up to 50mm a good rule of thumb is that an output of 10W/m is enough if the pipe lies in the ground or is otherwise covered. (A thin insulation is sufficient).

NOTE! A heating cable with an output greater than 12W/m must not be laid directly against a plastic pipe as this may cause heat damages to the pipe.

Velox Prefrost - the flexible tube with built- in heat

Using Velox Prefrost is the easy and quick way to get frost protected water pipes for a reasonable inclusive price.

In summer as in winter, Velox Prefrost guarantees problem‐free running water. It is a practical solution for workers sheds and other facilities of a non‐stationary type where water is to be installed.

Velox Prefrost is delivered as a ready unit, consisting of an insulated plastic tube (32mm), tee‐conduit and heating cables, ready mounted for connection to water and supply mains.

Velox Prefrost manages temperatures down to ‐25oC without further insulation.

Since the heating cable is fitted inside the tube, Velox Prefrost has a very high efficiency and consequently a very low energy consumption.

Velox Prefrost has been tested and approved by Statens Provningsanstalt (the National Swedish Institute for Materials Testing). The whole unit as well as its individual components are Semko‐marked.

Velox Prefrost is available in standard lengths according to the table above; other lengths on request.

VELOX PREFROST STANDARD KITS

Symbol Length Power (W) Part.o

Velox Prefrost (m) Total W/m

32/06 6 60 10.0 8986171

32/10 10 100 10.0 8986172

32/20 20 200 10.0 8986173

32/25 25 245 9.8 8986174

32/30 30 300 10.0 8986175

32/35 35 345 9.9 8986176

32/40 40 420 10.5 8986177

32/50 50 510 10.2 8986178

Other lengths on request


Frost protection with ready-made return-wire cable on pipes

TCPR return‐wire cable in standard loops for frost protection of pipes.

The cable loops are designed to give approximately 10W/m at 230 Volts. Cold‐lead‐in cable (1m). The TCPR‐cable is laid in one direction only and, consequently, the length of cable required is the same as the length of the pipe.

Length (m)

Power (tot W)

Power (W/m)

Part.no

6 60 10.0 8987150

12 110 9.1 8987152

20 220 11.0 8987154

25 265 10.6 8987156

30 330 11.0 8987158

35 375 10.8 8987160

40 455 11.5 8987162

45 405 7.0 8987163

50 556 11.0 8987164

55 506 9.0 8987165

60 675 11.0 8987166

65 625 7.5 8987168

70 755 11.0 8987170

80 805 10.0 8987172

85 950 11.0 8987174

90 904 10.0 8987175

100 1175 11.5 8987176

The heating cable loops are delivered with end termination, cold‐lead‐in cable and caution label.

At installations on rougher pipes, of type waste pipe, the cable can be spiralized. Contact our sellers for further information.


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Frost protection using standard loops

A very effective way to avoid ice forming in pipes is to install heating cables inside the pipes. This method has a very high efficiency, thus making it possible to manage difficult conditions with the use of low‐output cables.

The standard loops for internal frost protection are kept in stock in two different designs: return‐wire cable or self‐limiting cable.

At lengths between 1 ‐ 20m BTL is used and for lengths between 20 ‐100m TCPR is used.

The standard loops are designed for approx. 10W/m at 230 Volt.

All cables are delivered complete with cold‐lead‐in cable ends, R20 bushings and caution labels.

CABLE DATA

Length Power Type

(m) (tot) (W/m) TCPR BTL Part.no

1 10 10 X 140113I

2 20 10 X 1402025I

3 30 10 X 1403037I

4 40 10 X 1404050I

5 50 10 X 1405065I

6 60 10 X 1406075I

7 70 10 X 1407090I

8 80 10 X 1408110I

9 90 10 X 1409125I

10 100 10 X 1410135I

12 120 10 X 1412165I

14 140 10 X 1414190I

16 160 10 X 1416215I

18 180 10 X 1418245I

20 200 10 X 1420270I

20 200 10.0 X 8987124

25 245 9.7 X 8987125

30 300 10.0 X 8987126

35 345 9.9 X 8987127

40 420 10.4 X 8987128

45 370 8.3 X 8987129

50 510 10.2 X 8987130

55 465 8.5 X 8987131

60 620 10.4 X 8987132

65 575 8.8 X 8987133

70 690 10.4 X 8987134

80 930 11.6 X 8987135

85 875 10.3 X 8987136

90 930 9.2 X 8987137

100 1075 10.0 X 8987138


Frost protection using self- l imiting cable type BTL-10

BTL‐10 is a heating cable with self‐limiting properties. This cable is especially made for frost protection purposes, and can be used in external as well as in internal installations. With rising temperatures the output of the cable will decrease.

BTL‐10 provides approximately 12W/m at 0°C, about 10W/m at +10°C and if the temperatures increases to +65°C the output of the cable will be nearly zero.

BTL‐10 is sold prepacked in so‐called "frost boxes", containing 30, 50 or 100m cable together with an adequate number of termination kits and caution labels.

BTL‐10 can be cut to required lengths and the end termination is done on the site.

BTL‐10 is thus very suitable for keeping in stock, in order to take care of any sudden need for heating cables.

NAME CONTENTS

Frostbox Cable Termination kits

Caution labels

Part.no

BTL‐30 30 m 5 pcs 6 pcs 8986133

BTL‐50 50 m 10 pcs 10 pcs 8986135

BTL‐100 100 m 15 pcs 15 pcs 8986137

Control of frost protection installations

For easy and in most cases adequate control, use our OTTOSTAT (85 800 53).

The Ottostat is a thermostat permanently set to switch on at a temperature of +5°C, mounted in a junction box so that it senses the ambient air temperature. The junction box is equipped with the requisite number of connecting blocks and an indicator light.

If it should be more suitable to control the heating cable by a sensor, a cheap capillary thermostat, F2000, or a more expensive electronic one mounted on the pipe, can be used, which makes it possible to place the sensor at a distance up to 100m from the thermostat box. In both cases the sensor can be fitted to the pipe by using tape.

Name Temp. (°C)

Voltage (V)

Load (W/A)

Part.no

Ottostat (fast)+5 230 1300/6 8580053


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Notes

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Telephone: +46‐301‐418 40 – Email: [email protected] – Homepage: www.vkts.se

Industrihuset Södra Hedensbyn 43

S‐430 64 HÄLLINGSJÖ S‐931 91 SKELLEFTEÅ

Sweden Sweden

Fax: +46‐301‐418 70 Fax: +46‐910‐881 33

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Building site systems