In materials having burning rates differing according to the direction of the material (this being established by preliminary tests) the five (or more) samples shall be taken and be placed in the test apparatus in such a way that the highest burning rate will be measured.
Kui materjalil on eri suunas erinevad põlemistasemed (see tehakse kindlaks eelkatsel), võetakse viis (või rohkem) proovi ning asetatakse need katseseadmesse nii, et mõõdetakse suurimat põlemistaset.