In order to comply with the provisions of subregulation (1)(d), an employer must-
(a) ensure that the measurement programme, in the case of a group measurement, makes provision for the selection of the number of persons for a sample to be done as contemplated in Chapter 3 and 4 and Technical Appendix A of the OESSM: Provided that such sample size must be chosen for the top 10% of the group at the 95% confidence level for an HCA with a control limit, and for the top 10% of the group at the 90% confidence level for an HCA with a recommended limit; and
(b) subject to the criteria contained in regulation 6(1), carry out representative measurements at least every 24 months for an HCA with an OEL-ML or an OEL-RL as listed in Table 2 or 3 of Annexure 2.