Stelrad Correction Factor

For systems not operating at t50 the factors in the table below should be applied.

The output of a given radiator can be obtained by multiplying the quoted t50 output by the operating / correction factor.  Conversely, to derive a none t50 output, divide the heat output required by the relevant operation factor.  This ‘t50 equivalent output’ can then be used to select a radiator from the standard tables.

Delta T Correction Factor Delta T Correction Factor
20 0.302 43 0.821
21 0.322 44 0.846
22 0.342 45 0.871
23 0.363 46 0.897
24 0.383 47 0.922
25 0.404 48 0.948
26 0.426 49 0.947
27 0.447 50 1
28 0.469 51 1.026
29 0.491 52 1.052
30 0.513 53 1.079
31 0.535 54 1.105
32 0.558 55 1.132
33 0.581 56 1.159
34 0.604 57 1.186
35 0.627 58 1.213
36 0.651 59 1.241
37 0.675 60 1.268
38 0.699 61 1.296
39 0.723 62 1.324
40 0.747 63 1.352
41 0.7714 64 1.38
42 0.796 65 1.408
43 0.821

 

Example:
Exact output at t50 – 2,000 Btu/hr
Output at t30 = 2,000 x 0.513 = 1,026 Btu/hr
Average coefficient of 130 is used in the example above