1. Mixtures and preparations shall be treated in the same way as pure substances provided they remain within the concentration limits set according to their properties under the relevant provisions specified in CHIP, unless a percentage composition or other description is specifically given.
2. In the case of substances and preparations with properties giving rise to more than one classification the lowest thresholds shall apply.
3. Where a substance or group of substances listed in Part A also falls within a category of Part B, the controlled quantities set out in Part A must be used.
4. In the case of an establishment where no individual substance or preparation is present in a quantity above or equal to the relevant controlled quantity for that substance or preparation, the addition of hazardous substances to determine the controlled quantity shall be carried out according to the following rule:
If the sum—q1/Q + q2/Q + q3/Q + q4/Q + q5/Q + ... ≥ 1
(where qx = the quantity of hazardous substance x (or category of substance) present, Q = the relevant controlled quantity (Q) from Part A or B, except for those substances for which column 3 of Part A contains a quantity Q*, in which case the quantity Q* shall be used in place of the controlled quantity Q in column 2)
then the controlled quantity of each of the substances which are added together in accordance with each of paragraphs 5(a) to (c) below shall be deemed to be present for the purposes of sections 108(1), 112(2)(a), 117(2)(a) of the 2011 Act and of section 149 (enforcement notice to have effect against subsequent development) of the 2011 Act as modified by regulation 17(1) and Part 2 of Schedule 3 to these Regulations.
5. The addition rule in paragraph 4 will apply for the following circumstances:—
(a)for the addition of substances and preparations named in Part A and classified as toxic or very toxic, together with substances and preparations falling into categories 1 or 2 of Part B;
(b)for the addition of substances and preparations named in Part A and classified as oxidising, explosive, flammable, highly flammable or extremely flammable, together with substances and preparations falling into categories 3, 4, 5, 6, 7, 8 or 9 of Part B;
(c)for the addition of substances and preparations named in Part A and classified as dangerous for the environment (R50 (including R50/53) or R51/53), together with substances and preparations falling into categories 10(i) or 10(ii) of Part B.