The entrance of gases from the fires into the smelting room shall be prevented as far as possible by suitable arrangements for drawing them off. 10. Sieving and packing of by-products obtained in the distillation of zinc skimmings (poussière, flue dust) shall not be done except in a special room separated from the other workrooms, and complying with the requirements of Reg. 1. Sieving shall only be done in an apparatus so constructed that dust shall not escape. _Employment of workers._ 11. Women and young persons shall not be employed or permitted in rooms mentioned in Reg. 1, in flue dust chambers, or dust flues, or in the removal of flue dust. 12. No person shall be newly employed in rooms mentioned in Reg. 1, in flue dust chambers, or dust flues, or in the transport of flue dust, without a certificate of fitness from the surgeon appointed by the higher authorities. These certificates shall be collected and shown to the Factory Inspector and Appointed Surgeon on request. 13. No person shall be employed in charging blast furnaces, apart from mere labouring work on the floors, for more than eight hours daily. The same shall apply in the case of workmen employed in the inside of furnaces when cool, or in emptying flue dust chambers, or dust flues which contain wet flue dust. No person shall be employed in cleaning out, from inside, flue dust chambers, or dust flues containing dry flue dust for more than four hours daily; and including emptying and work of transport of this kind altogether no longer than eight hours daily. Other workers in rooms specified in Reg. 1 shall not work more than 10 hours in 24, exclusive of mealtimes. Exception to this is allowed in the case of those workers who are employed for the purpose of a weekly change of shift, and for whom exception as to Sunday employment is permitted by Imperial Decree. _Clothing, overalls, lavatory accommodation, &c._ 14. The occupier shall provide for all persons employed in cleaning out flue dust chambers, dust flues, repairing of cooled furnaces, grinding, sieving and packing of litharge, red lead, or other lead colours, complete suits of working clothes, including caps and respirators. 15. Work with lead salts in solution shall not be done except by workers who either grease their hands or are provided with impermeable gloves.