Dear avila muncar,
I assume it was brc sec. 3.5.1.1 which mainly initiated yr OP. (also overlaps subsequent clauses).
Please see thread linked below, eg posts #7, 19 and the surrounding discussion. All of the thread is interesting IMO.
Note that this thread was oriented to ver.6 and some changes have occurred in ver.7, eg questionnaires, scope.
This whole categorization topic IMO is highly subjective regarding terminologies.Just like haccp. Pros and Cons of course.
(BTW - This topic is also overviewed in the free (used to be anyway, now unsure) BRC enrollment guideline documents and the brief text there suggested (to me) that BRC are not anticipating masterpieces of risk analysis.)
Resuming, 2 previous threads (for BRC version 6 [which is very similar to ver.7 on this topic]) are useful, first one (2014) is -
http://www.ifsqn.com...isk-assessment/
A second informative thread (2012) also for ver.6, is -
http://www.ifsqn.com...-6-clause-3511/
#7 of 2nd thread directly addresses the scope of 3.5.1.1 (including "quality"). The detailed basis for the stated Risk results and audit frequency are perhaps detailed elsewhere.
@Madame A.D-tor - After some deconvolution/simplifying/combining of the BRC clauses 3.5.1.1 and 3.5.1.2, it seems one could state that –
Both Supplier Approval and Monitoring = f (RA[input[intrinsic-process-customer usage]] / [supplier cert.status / questionnaire / audit[procedure-frequency]])
I think this is In agreement with yr H-L-L-H philosophy. 
Rgds / Charles.C
PS - as I understand, BRC does not explicitly require you to designate a supplier of raw material as intrinsically L/H risk. No definition of a HR Supplier is mentioned in the standard. It is understandable to associate a HR Ingredient with a HR Supplier but the designation is liable to misinterpretation.
AFAIK, BRC is requiring, via compliance with its clauses, that the manufacturer demonstrate a methodology so as to ensure that an input from any Approved Supplier will, ultimately, not present a significant risk with respect to the end product’s agreed characteristics, safety or non-safety.