Strength classes you won’t find in EN338

Not all strength classes are listed in EN338. Here are the main characteristic properties of some strength classes that appear in machine settings tables for machine controlled grading in Europe.  (The other design properties can be calculated from the equations in EN384). Many of these are not available on the general market, or even in current use in a manufacturing process – but TR26 is a prime example of a commonly traded non-EN338 strength class (at least in the UK market).

Note this previous advice though – in this case, the primary references will be the latest tables of machine settings (known as AGRs or ITTs). These are available most easily from grading machine manufacturers, but can also be obtained through the SG18 group of Notified Bodies.  Everything you will find in EN14081-4 is out of date / replaced by AGRs / ITTs.

Strength class5%ile bending strength (N/mm2)5%ile tensile strength (N/mm2)Mean modulus of elasticity (kN/mm2)5%ile density (kg/m3)Comments
C36T2236.713390
E153615420
NapierDA3513460A grade for Douglas-fir from UK and IE
E143214400
E133013380
NapierDB3012460A grade for Douglas-fir from UK and IE
NapierLA3013480A grade for larch from UK
TR2628.311370A grade for trussed rafters in the UK
NapierLB2812440A grade for larch from UK
C25T152511.5360
E12.52512.5370
NapierSA2511375A grade for spruce from UK and IE
E122412370
NapierSB2210360A grade for spruce from UK and IE
NapierLC219400A grade for larch from UK
NapierLD208390A grade for larch from UK
C16+18.58330A grade for spruce from UK and IE
E8.5188.5320
NapierDC1610400A grade for Douglas-fir from UK and IE
NapierSC168320A grade for spruce from UK and IE
NapierSD157310A grade for spruce from UK and IE
batten14147.5330A grade for spruce tiling battens from UK and IE
NapierDD149400A grade for Douglas-fir from UK and IE
batten12127.5330A grade for spruce tiling battens from UK and IE
batten10107330A grade for spruce tiling battens from UK and IE
L402614420
LD262614410
L362213400
LD222213390
L301812380
LD181812370
L271611.5370
L2514.511350
LD1514.511350
L221310340
L17119320
LD11119320

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