3.—(1) These Regulations shall apply within the territorial sea only to and in relation to the premises and activities to which any of paragraphs 2 to 6 of Schedule 4 applies.
(2) Subject to Schedule 1 (which sets out exceptions to the Regulations), these Regulations shall apply to or in relation to pressure systems which are used or intended to be used at work.
(3) Any requirement or prohibition imposed by these Regulations on an employer in respect of the activities of his employees shall also extend to a self-employed person in respect of his own activities at work.
(4) Any requirement or prohibition imposed by these Regulations on a person –
(a)who designs, manufactures, imports or supplies any pressure system, or any article which is intended to be a component part of any pressure system, shall extend only to such a system or article designed, manufactured, imported or supplied in the course of a trade, business or other undertaking carried on by him (whether for profit or not);
(b)who designs or manufactures such a system or article shall extend only to matters within his control.
(5) The provisions of Schedule 2 (which relate to the modification of duties in cases where pressure systems are supplied by way of lease, hire or other arrangements) shall have effect.