Section 20 - Thermal Electric Elements

Section 20 Technical Information

Page

Calculation for Superheated Steam

20.1

Watt Density to Element Sheath Temperature

20.3

Sheath Temperature

20.4

Heat Loss

20.5

Pressure Drop

20.7

Air Heating

20.8

Formulae and Conversion Tables

20.9

Quick Reference Charts

20.14

AUSTRALIA AUSTRALIA HEATING SOLUTION PROFESSIONALS THE SPECIALISTS IN CUSTOM HEATING

20.1 Calculation for Superheated Steam Example: 340kg per hour of steam with 90% quality, having an inlet gauge pressure of 700kPa is to be superheated to a temperature of 230°C. How many kilowatts of power is required? From the reference guide (see next page): 1. Plot a point equalling 700kPa on the centre reference line of the pressure and saturated temp scale (P). 2. From that point, mark a line through 90% on the quality scale (Q) to the watt hour/weight scale (W). The answer is 82.5 Watts/kilogram. 3. Note that the saturated temperature of steam at 700kPa is 170°C. A temperature of 230°C is required, therefore a 60°C temperature rise is needed. 4. From the point of 700kPa plotted on the centre reference line of P, mark a line through 60°C on the S scale to the W scale. The answer is approximately 200 Watts/kilogram. 5. Subtract 82.5 from 200 = 117.5 6. Power required Always add 20% for loss Total power Answer

= Weight x Watt hour/kilogram = 340kg x 117.5 = 39,950 Watts + 7,990 Watts = 47,940 Watts = 48kW

Definitions Saturated Temperature is the temperature at which water boils at a given pressure. At zero gauge pressure the temperature is 100°C (212°F), as steam pressure increases the saturated temperature increases - refer to the P reference scale. Quality of Steam is the amount of moisture present in the steam, which is measured as the percentage of the total weight. Quality of steam 100% minus the percentage of moisture content, therefore dry steam has 100% quality. Degrees of Superheat is the increase of steam temperature above the inlet saturated temperature. Watt hour per Weight is the power required to superheat the steam above the saturated temperature. This is known as Watts per hour per kilogram (pound) required. Weight of Steam per hour is the flow rate of steam which will be passing through the electric heating unit per hour. This information is vital for the most efficient design of the heater.

AUSTRALIA THE SPECIALISTS IN CUSTOM HEATING

20.2

Quick Reference Guide for Electrically Heated Steam


20.3 Watt Density to Element Sheath Temperature

These temperatures are calculated based on a 20˚C ambient (70˚F) in still air

Watt Density kW/m² 1.55 3.1 4.0 4.6 6.2 7.75 9.3 12.4 15.5 18.6 23.25 31.0 38.75 46.5 54.25 62.0 70.0 77.5 93.0 108.0 124.0

W/cm² 0.16 0.3 0.38 0.46 0.62 0.78 0.93 1.24 1.55 1.86 2.32 3.10 3.88 4.65 5.42 6.20 7.0 7.75 9.3 10.8 12.4

W/in² 1 2 2.5 3 4 5 6 8 10 12 15 20 25 30 35 40 45 50 60 70 80

Sheath Temp °C 90 135 155 175 215 260 290 360 400 450 485 530 580 650 685 710 750 800 860 930 950

°F 195 275 310 350 420 500 555 680 750 840 905 985 1075 1200 1265 1310 1380 1470 1580 1705 1740

Surface temperature will vary depending on the application


20.4 Sheath Temperature

Thermal tubular heating elements sheath temperature in still & moving air

80

124 115

70

100

60

90 80

10 m/s

5 m/s

50

Still Air

45

70

W A T T

3 m/s 2 m/s

60

40 35

W A T T

50 30 D E N S I T Y kW/m

40

25 20

30 2

15

D E N S I T Y W/in

20 10 10 5 0

0 100

200

300

400

500

600

700

800

900

1000

Sheath temperature °C


2

20.5 Heat Loss Losses - Uninsulated metal surfaces T E M P E R A T U R E D I F F E R E N C E

C

500

B

A

A. Oxidised aluminium vertical surfaces

C

B. Oxidised steel bottom & horizontal surfaces

450

C. Oxidised steel vertical surface losses from tanks, pipes etc

400

350

100

300

80

250

60

200

40

150

20

C A

.2

.4

.6

.8

15

20

25

30

1

100 0

5

10

KILOWATTS PER SQUARE METRE - kW/ m2

Losses - Open water tanks

100

T E M P E R A T U R E

90

O F

60

W A T E R C

80

70

50

40

30 0

2

4

6

8

10

12

KILOWATTS PER SQUARE METRE OF WATER SURFACE - kW/ m 2


14

16

20.6 Heat Loss - continued Losses - Surfaces of oil baths 350

Losses - Insulated wall for ovens, tanks, pipes, etc 600

300 100 mm INSULATION

T E 500 M P E R A 400 T U R E

75 mm INSULATION

250

50 mm INSULATION

200

300

D I F F E 200 R E N C 100 E

150

25 mm INSULATION

100

° C

0 0

100

200

300

400

500

600

WATTS PER SQUARE METRE - W/

700

800

50

900

m2

0 0

2

4

6

8

10

12

KILOWATTS PER SQUARE METRE - kW/m2

Losses - For pipe lines Losses - Molten Metal Surfaces

400

450 350 T E M P E R A T U R E D I F F E R E N C E ° C

P I P E T O A M B I E N T T E M P

25mm PIPE

400

300 50mm PIPE 250

200 100mm PIPE 150 200mm PIPE

100

T E M 350 P E R A T 300 U R E C° 250

50

200 0 0

2

4

6

8

10 2

20

40

60

80

100

120

140

160

180

200

250

KILOWATTS PER SQUARE METRE - kW/m

WATTS PER METRE - W/m


12

20.7 Static pressure drop for Thermal tubular air heaters (unfinned)

Pressure Drop (forced air)

7

O U T L E T V E L O C I T Y

6 A 1 Row B

A 3 Rows B

5 A 6 Rows B 4

3

Thermal tubular air heaters A - 8mm Dia nominal sheath B - 11mm Dia nominal sheath

M3 2 / S 1

0 0

5

10

15

20

Static Pressure drop in Pascals (Pa)

Static pressure drop for Thermal finned tubular air heaters 7 1 Row

O U T L E T V E L O C I T Y

6 2 Rows 3 Rows

5

6 Rows

4

3

Thermal finned air heaters 11mm Dia nominal sheath 32mm Dia fins @ 5mm fin pitch

3 M 2 / S

1

0 0

10

20

30

40

50

60

Static pressure drop in Pascals (Pa)


70

25

30

35

20.8 Air Heating Kilowatts required for air heating 400

350

300

K 250 I L O W A 200 T T S 150

KW 100

50

0 0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

LITRES PER SECOND AIR FLOW - L/S

Recirculated air heating with Thermal finned tubular heaters 65

100

60

90

150 °C

200 °C

250 °C

55

W 80 A T T

50

70 D E N S I T Y

45 40

60

35

Thermal finned air heaters 11mm Dia nominal sheath 32mm Dia fins @ 5mm fin pitch

50

kW/m2

30

40

W A T T D E N S I T Y W/in2

23

30

20

0

1

1.5

2

2.5

3

3.5

4

Air velocity - m³/s


20.9 Formulae and Conversion Tables To calculate kW required to raise the temperature of a product, the following formula may be used. This formula provides net kW to raise temperature by a desired degree in a desired time. It does not allow for inefficiencies due to heat loss through insulation etc. or changes of state.

V x p x Cp x ΔT t

=

kW required

V = Volume required (m3) p = Density (kg/m3) Cp = Specific heat capacity (kJ/kg.K) ΔT = Required temperature change (°C) t = Required heating time in seconds Note: 1. (V x p) can be substituted by kg in this formula when heating solids such as metals. 2. 1000 litres = 1m³ For flow line heating use m³ per hour flow rate to achieve kW and/or ΔT. For more accurate check use the following formula:

kW x 3600 4.187 x ΔT

=

m³/h (For water only)

Forced air heating formula

Example: Air is circulated through a heater duct by a 1000CFM blower. The air enters the duct at 35°C and is heated to 120°C Select one of two formulae: 1. kW = m³/s x ΔT x 1.278 2.

Convert 1000 CFM to L/s (refer to table) = 1000 x 0.472 = 472 litres/sec kW = L/s x ΔT = 472 x 85 783 783 kW = 51.25 20% safety factor = 10.25 kW = 61.50 The heaters required will total 62kW


20.10 AVERAGE SPECIFIC HEAT CAPACITY (Cp)

Gases and Vapours

Substance Acetylene Air Ammonia Carbon Dioxide Chlorine Ethane Ethylene Flourine Hydrochloric Acid Hydrogen Methane Nitrogen Oxygen Water Vapour (100°C) Steam Sulphur Dioxide

Metric Imperial Metric Imperial lb/ft³ kJ/kg.K Btu/lb.F kg/m³ 0.35 0.073 1.169 1.465 0.240 0.080 1.281 1.005 0.520 0.048 0.769 2.177 0.203 0.123 1.970 0.850 0.125 0.20 3.203 0.523 0.43 0.109 1.74 1.800 0.40 0.073 1.66 1.675 0.179 0.136 2.18 0.749 0.195 0.102 1.634 0.816 3.41 0.0056 0.090 14.277 0.60 0.045 0.716 2.512 0.245 0.078 1.249 1.025 0.218 0.09 1.442 0.913 0.460 0.050 0.80 1.926 0.649

AVERAGE SPECIFIC HEAT CAPACITY

Substance ABS

Plastics

Acrylic

Polyester Polyethylene

Polystyrene PVC

DENSITY (p)

0.155

2.867

0.179

SPECIFIC MAX RECOMMENDED GRAVITY SERVICE TEMP

Metric Imperial H2O = 1 kJ/kg.K Btu/lb.F at 4°C 1.04 1.46 0.35 0.4 1.06 1.67 0.35 1.17 1.46 1.19 1.3 1.09 0.26 0.55 1.45 2.30 0.55 0.91 2.30 0.93 1.04 1.34 0.32 0.35 1.07 1.46 0.3 1.2 1.26 0.5 1.55 2.09

Metric Imperial °F °C 150 66

60 71 149

140 160 300

120

250

60

140

71 65 75

160 150 170


20.11 Liquids AVERAGE SPECIFIC HEAT CAPACITY (Cp)

LATENT HEAT OF FUSION OR EVAPORATION

BOILING POINT

DENSITY (p)

Metric Imperial Metric Imperial Metric Imperial Metric Imperial lb/ft³ kg/m³ °F °C Btu/lb kJ/kg.K Btu/lb.F kJ/kg Substance 0.47 65.5 1049 244 118 174 404.7 1.968 Acetic Acid (100%) 0.514 49.3 790 42.3 98.3 2.152 Acetone 0.711 50.9 816 217 504.8 2.977 - Amyl 0.548 856.07 49.3 789 172 78 368 2.294 - Ethyl 0.107 198.7 3184 136 58 86 200.06 0.448 Bromine 0.58 79.38 1271.4 554 200 76.1 711.03 2.428 Glycerine 0.35 88.6 1420 26.8 62.34 1.465 Honey 0.74 78.6 1259 185 85 Hydrochloric Acid (10%) 3.098 0.5 51.1 819 105 244.3 2.094 Kerosene -110 -255.9 0.610 49.4 791 42.5 98.8 2.554 Methylated Spirits 0.93 64.2 1029 3.894 Milk 0.434 59.9 959 1.817 Oil - Caster 0.44 58.2 933 1.842 - Linseed 0.40 56.7 909 1.675 - Lubricating 0.471 57.2 917 572 300 1.972 - Olive or Palm 49.9 799 750 300 2.177- 0.520.71 63.2 147 2.973 - Paraffin 0.46 54.2 869 1.926 - Transformer 0.511 309.39 54.7 877 100381332.140 Petroleum 399 204 145 -337.31 63.9 1023 214 101 3.936- 0.94Sea Water 0.98 4.103 0.835 132.8 2128 2530 1388 3.496 Sodium Hydroxide (100%) 0.344 511.78 114.2 1829 590 310 220 1.440 Sulphuric Acid (100%) 0.50 58.6 939 90 32.2 81 188.43 2.094 Tallow 0.440 55.0 881 232 111 156 362.9 1.842 Toluene 0.472 54.1 866 300 149 133 309.4 1.976 Turpentine 65.5 1049 244 118 Vinegar 1.00 62.4 999 212 100 970 2256.5 4.187 Water


20.12 Metals & Alloys AVERAGE SPECIFIC HEAT CAPACITY (Cp)

Substance Aluminium Cast Antimony Arsenic Brass Bronze (Comm) Cast Iron (Grey) Copper Gold

Gunmetal Iron (99.9%) - Wrought

Lead - Melted - Solid Magnesium Mercury Nickel Silver Solder Steel Tin - Solid - Melted Type Metal (85%) Lead (15%) Antimony Zinc


MELTING POINT

DENSITY (p)

Metric Imperial Metric Imperial Metric Imperial Metric Imperial lb/ft³ kg/m³ °F °C Btu/lb kJ/kg.K Btu/lb.F kJ/kg 0.255 321.03- 138.17 168.4 2697 1220 660 0.942 395.47 250.209- 0.050-0. 58.16052 412.8 6613 1166 630 44 102.36 0.218 0.082 356.7 5714 1500 819 0.343 0.09527.5 8451 2280 1249 84.4 196.34 0.3770.10 0.419 0.104 540.6 8661 2150 1177 0.435 443.3 7102 0.498- 0.1190.13 41.4 96 0.544 557.5 8930 1981 1083 78 0.384- 0.092 181.45 0.126 0.527 0.0316 19279 158086028.7 66.79 0.132 1023.5 1940 1060 0.107 197.87 542.5 8691 84.2 0.448 490.1 7852 2795 1535 40 0.461- 0.110- 93.05 0.130 0.544 0.11473920.4770.12 461.40.502 492.6 7981 0.04 0.167 0.031 710.8 11388 621 327.5 11 25.59 0.130 0.25 108.5 1738 1204 651 160 372.2 1.047 0.033 272.18 848 13855 243 117 75.16 0.138 0.11 550 8810 2642 1450 127.7 297 0.461 0.057 655 10492 1761 961 38 88.39 0.239 0.04 580 9291 415 213 17 39.54 0.167 0.12 490 7849 2550 1399 0.502 0.056 455 7288 450 232 25.0 58.15 0.234 0.064 0.268 0.040 670 10732 500 260 1.674

0.398

0.095

118.63

51

419

787

7128

445


20.13 Solids AVERAGE SPECIFIC HEAT CAPACITY (Cp)

Substance Asphalt Basalt Butter, Lard Celluloid Glass - Crown Graphite Gypsum Ice Iodine Pitch Resin Rubber Salt Soil Sugar Vegetalo Vinyl Wax

- Soft Paraffin - Hard Paraffin White, Bees



BOILING POINT

DENSITY (p)

Metric Imperial Metric Imperial Metric Imperial Metric Imperial lb/ft³ kg/m³ °F Btu/lb °C kJ/kg.K Btu/lb.F kJ/kg 0.4 68.6 1099 104 93.05 40 40 1.674 0.199 149.7 2397 984 529 0.833 0.467 58.0 929 90 32 1.955 0.32 84.2 1349 140 60 1.339 0.18 149.7 2397 2058 1126 0.754 0.670- 0.160.454 140.3 2248 7592 4200 1.633 0.259 144.7 2317 2660 1460 1.084 0.5 56.1 899 212 100 334.98 144 2.093 0.053 308.0 4935 2360 1293 62.2 26.7 0.217 66.710690.5 71.7 1149 300 149 116.31 50 2.093 0.05 199.5 3197 178 81 2.093 56.7829208981.130- 0.270.48 58.0 908 347 175 2.010 0.21 130.9 2098 2669 1465 0.879 0.5 74.811993002 1650 2.093 99.8 1598 0.30 100.4 1608 320 160 1.252 0.80 57.7 924 95 35 3.349 6911002121001.256- 0.300.50 91 1450 500 260 2.093 54.28691003863 2.889- 0.69- 146.56 0.71 54.9 879 125 52 2.973 54.9879125522.889- 0.69- 177.03 76.1 0.71 58.0 929 133 56 2.973 0.35 59.2949144 62 1.465 174.47 75 59.9 959

20.14 Quick Reference Charts Kilowatts to heat steel in 1 hour kg’s of Steel 10 25 50 100 150 200 250 300 350 400 500 1000

10 0.017 0.042 0.085 0.17 0.26 0.34 0.42 0.51 0.6 0.68 0.84 1.7

25 0.042 0.1 0.21 0.42 0.63 0.84 1 1.26 1.5 1.7 2.1 4.2

50 0.085 0.21 0.42 0.85 1.27 1.7 2.1 2.5 3 3.5 4.2 8.4

Temperature Rise in °C (∆T) 100 150 200 250 0.17 0.25 0.34 0.42 1 0.42 0.64 0.85 2 1.7 0.85 1.3 4.2 3.4 2.5 1.7 6.3 5 3.8 2.5 8.5 6.8 5 3.4 8.5 10.5 6.3 4.2 7.5 10.2 12.6 5 15 12 9 6 17 10.2 13.6 7 21 8.4 12.6 16.8 42 34 16.8 25.2

300 0.5 1.27 2.6 5 7.5 10.2 12.6 15.3 18 20.4 25.2 50.5

400 0.68 1.7 3.4 7 10 13.6 16.8 20.5 24 27.2 33.6 67.5

350 0.6 1.5 3 6 9 12 15 18 21 24 30 60

** Includes +20% tolerance to allow for high heat loss situations or low power voltage.

kW = Example:

V x p x Cp x ΔT t

or

kg x 0.502 x ΔT t

To heat 10kg of Steel from 10°C to 20°C in 5 minutes From table:

0.017kW to heat in 1 hr, therefore to heat in 5 minutes 0.017 x 12 = 204W required

Example:

To heat 500kg of Steel from 100°C to 200°C in 4 hours From table:

8.4kW to heat in 1 hr, therefore to heat in 4 hours 8.4kW ÷ 4 = 2.1kW required


20.15 Kilowatts to heat water in 1 hour Litres of Water 5 10 20 50 100 200 300 400 500 750 1000 1500 2000 2500 3000 5000 10000

10 0.07 0.14 0.28 0.7 1.4 2.8 4.2 5.6 7 10.5 14 21 28 35 42 70 140

30 0.21 0.42 0.84 2.1 4.2 8.4 12.6 16.8 21 31.5 42 63 84 105 126 210 420

20 0.14 0.28 0.56 1.4 2.8 5.6 8.4 11.2 14 21 28 42 56 70 84 140 280

Temperature Rise in °C (∆T) 70 60 50 40 0.28 0.35 0.42 0.49 0.56 0.7 0.84 0.98 2 1.7 1.12 1.4 4.9 4.2 3.5 2.8 9.8 8.4 7 5.6 16.8 19.6 14 11.2 25.2 29.4 21 16.8 33.6 39.2 28 22.4 49 42 35 28 73.5 63 52.5 42 98 84 70 56 147 105 126 84 196 112 140 168 245 140 175 210 294 252 168 210 490 280 350 420 980 560 700 840

100 90 80 0.56 0.63 0.7 1.12 1.26 1.4 2.8 2.5 2.25 7 6.3 5.6 14 11.2 12.6 28 22.4 25.2 42 33.6 37.8 56 50.4 44.8 70 63 56 94.5 105 84 112 126 140 168 189 210 224 252 280 280 315 350 336 378 420 560 630 700 1120 1260 1400

** Includes +20% tolerance to allow for high heat loss situations or low power voltage.

kW = V x p x Cp x ΔT

t

Example:

To heat 2000L of Water by 70°C in 4 hours From table:

= 196kW/h, therefore = 196 ÷ 4 = 49kW required

Example:

To heat 10L of Water to 100°C from ambient temperature of 20°C in 10 minutes From table:

= 1.12kW x 6 = 6.72kW required


20.16 Kilowatts to heat Oil in 1 hour Litres of Oil 5 10 20 50 100 200 300 400 500 750 1000 1500 2000 2500 3000 5000 10000

Temperature Rise in °C (∆T) 200 250 300 100 150 75 50 25 10 0.9 0.6 0.75 0.03 0.075 0.15 0.23 0.3 0.45 1.8 1.5 1.2 0.9 0.06 0.15 0.3 0.46 0.6 3.6 3 2.4 1.8 0.6 0.92 1.2 0.12 0.3 9 7.5 6 4.5 3 2.3 0.3 0.75 1.5 18 15 12 9 6 4.6 3 1.5 0.6 36 30 24 18 12 9.2 6 3 1.2 54 45 36 27 18 13.8 9 4.5 1.8 72 60 48 36 24 18.4 12 6 2.4 90 75 60 45 30 23 15 7.5 3 135 112.5 90 67.5 45 33.8 4.5 11.25 21.6 120 150 180 90 60 46 30 15 6 180 225 270 135 90 22.5 43.2 67.6 9 240 300 360 120 180 92 60 30 12 300 375 450 37.5 73.2 113.6 150 225 15 360 450 540 86.4 138 180 270 45 18 600 750 900 75 146.4 227 300 450 30 150 293 454 600 900 1200 1500 1800 60

** Includes +20% tolerance to allow for high heat loss situations or low power voltage. ** For lubricating oils decrease values by 17%

kW = V x p x Cp x ΔT

t

Example:

To heat 1500L of Oil to a temperature of 100°C in 15 hours From table:

= 90 ÷ 15 hours = 6kW required

Example:

To heat 10L of Oil from 100°C to 200°C in 20 minutes From table:

= 0.6kW x 3 = 1.8kW required


20.17 Ohms Law VALUES AT 240V

Watts 100 200 300 400 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 4000 4500 5000 5500 6000


VALUES AT 110V

VALUES AT 415V

Ohms Amps Ohms Amps Ohms Amps 0.25 1722 0.9 121 0.4 576 0.48 861 1.8 60.5 0.83 288 0.72 574 2.7 40.3 1.25 192 0.96 430 3.6 30.25 1.6 144 1.2 344 4.5 24.2 2.08 115 1.8 229 6.8 16.1 3.1 76 2.4 172 9 12.1 4.16 57 3 137 11.3 9.7 5.2 46 3.6 114 13.6 8 6.25 38 4.2 98 15.9 6.9 7.3 33 4.8 86 18.1 6 8.3 28 5.4 76.5 20.4 5.3 9.3 25 6 69 4.85 22.75 10.4 23 6.6 62 25 4.4 11.4 21 7.2 57 27.2 4 12.5 19 7.8 53 29.5 3.72 13.5 17.7 8.4 49 31.8 3.45 14.6 16.4 9 45.9 34 3.22 15.6 15.3 9.6 43 36.3 3 16.6 14.4 10.8 38 41 2.7 12.8 18.75 12 34.4 45.5 2.42 20.8 11.5 13.2 31 50 2.2 23 10.5 14.4 28.7 54.5 2 25 9.6

20.18 Density Kilogram per cubic metre (kg/m³)

Pound per cubic inch (lb/in³)

Pound per cubic foot (lb/ft³)

1 27.68 x 10³ 16.02

0.036 x 10-3 1 0.578 x 10-3

0.0624 1728 1

Millimetres (mm)

Metres (m)

Inches (in)

Feet (ft)

1 1000 25.4 304.8

10-3 1 0.0254 0.3048

0.03937 39.37 1 12

0.00328 3.28 0.0833 1

Square Millimetres (mm2)

Square Metres (m2)

Square Inches (in2)

Square Feet (ft2)

1 106 645.16 92.903 x 10-3

10-6 1 0.645 x 10-3 0.0929

1.55 x 10-3 1550 1 144

0.01076 x 10-3 10.764 6.949 x 10-3 1

Kilogram (kg)

Metric Ton (Tonne = 1000kg)

Pound (lb)

UK Ton (Ton)

1 1000 0.454 1016

10-3 1 0.454 x 10-3 1.016

2.205 2205 1 2240

0.984 x 10-3 0.984 0.461 x 10-3 1

Length

Area

Mass


20.19 Energy British Thermal Unit ( Btu) 1 0. 948

Kilo jo ule ( kj) 1.06 1

British Thermal Unit (Btu) 3412 1

Kilo w att (kW) 1 0.293 x 10 -3

Power

Watt Density Watt p er S q uare Inc h (Watt/in2) 1 0. 645

Kilo w atts p er S q uare Metre ( kW/m2) 1.55 1

Specific Heat Capacity Btu/lb.°F 1 238. 8 0.2388

J/kg.K 4.187 x 10 -3 1 103

kJ/kg.K 4.187 10-3 1

Newton ( N) 9.807 1 4. 448

Pound Force ( lb f) 2.205 0. 225 1

Force Kilogram Fo rc e ( kgf) 1 0. 102 0. 454


20.20 Velocity Feet per minute (ft/min) 60 1 196.85 3.28

Metres per second (m/s) 0.305 0.005 1 0.0167

Metres per minute (m/min) 18.29 0.305 60 1

Millimetre Mercury (mmHg) 25.4 1 2.036 0.2953

Pound Force Square Inch (lbf/in2) 39.09 x 10-3 0.4912 1 0.145

Kilopascal (kPa) 0.2486 3.386 6.895 1

Feet per second (ft/s) 1 0.0167 3.28 0.055

Pressure Inch Water (inH2O) 1 13.161 27.70 4.02

Volume Cubic Cubic metres millimetres (m3) (mm3) 10-9 1 1 109 10-3 106 16.4 x 103 1.64 x 10-6 0.0283 28.32 x 103 0.0045 4546 x 103

Imperial Cubic Cubic gallon feet inches Litre (gal) (ft3) (in3) (L) 61.023 x 10-6 0.353 x 10-9 0.220 x 10-6 10-6 219.9 61.023 x 103 35.315 103 0.0220 0.035 61.023 1 0.578 x 10-3 3.6 x 10-3 1 1.64 x 10-3 6.229 1 1728 28.316 1 0.1605 277.46 4.546

Volume rate of flow Gallons Litres Cubic foot Cubic foot per second per minute per second per minute (gal/min) (L/s) (ft3/min) (ft3/s) 373.2 28.316 60 1 6.229 0.472 1 0.016 13.2 1 2.119 0.035 1 0.076 0.1605 0.003 13.19 x 103 1 x 103 2119 35.315 219.9 16.6 35.315 0.588

Cubic metres Cubic metres per second per minute (m3/s) (m3/min) 0.028 1.68 0.47 x 10-3 0.0283 1 x 10-3 60 x 103 0.076 x 10-3 4.56 x 103 1 60 0.016 1


20.21

Temperature conversion table °C

°F

°C

°F

°C

°F

0 50 100 150 200 250 300 350 400 450 500 550 600 650

32 122 212 302 392 482 572 662 752 842 932 1022 1112 1202

700 750 800 850 900 950 1000 1050 1100 1150 1200 1250 1300 1350

1292 1382 1472 1562 1652 1742 1832 1922 2012 2102 2192 2282 2372 2462

1400 1450 1500 1550 1600 1650 1700 1750 1800 1850 1900 1950 2000 2050

2552 2642 2732 2822 2912 3002 3092 3182 3272 3362 2452 3542 3632 3722

The tables provided are a guide to assist you in calculating your heating requirements. For advice on your individual needs, contact our Design department for further technical information.


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