There were two broad types of breathing apparatus in general use for the purpose of affording respiratory protection against poisonous or irrespirable atmospheres. These were: - (1) Tube Breathing Apparatus; (2) Self-contained Breathing Apparatus. (3) Escape Apparatus. recommendations were made by the Chief Inspector of Mines that simple and suitable self-rescuers should be provided for men working underground

Tube Breathing Apparatus.

The Fourth Schedule to the General Regulations (Rescue) 1928 required each Central Rescue Station to maintain 4 sets, and each colliery employing 100 or more persons underground one set, of tube breathing apparatus. The eighth Schedule to the regulations required the official calling assistance in case of emergency to requisition the "smoke helmet" or other apparatus serving the same purpose.

1.- Helmet Type. This type of apparatus allowed the wearer to go a limited distance into a dangerous atmosphere by obtaining fresh air, forced through a tube, from a point beyond poisonous area. The Spirelmo type comprised a leather helmet with an apron which completely enveloped the head of the wearer; the fresh air being delivered to him, through an air tube of two-ply canvas insertion rubber with an internally embedded wire armour and an external canvas fabric covering. The air was pumped into the helmet by means of a hand or foot operated bellows worked by another person. The air tube is 3/4"diameter, usually in 2-60ft. lengths, and fitted with screwed unions. Ivan Briggs wearing smoke helmet and Asst Superintendent Radford on bellows.

When in use it was vital for the bellows to be operated continuously, to supply a continuous flow of fresh air to the wearer, and to maintain a pressure above that of the atmosphere, in the helmet.

2.- Equaliser Types.
In these types of apparatus bellows were not used, but a rotary blower might or might not be used.
All these apparatus were fitted with an air flow equalising device which had the function of converting the intermittent flow of air to a very nearly uniform flow, thereby reducing the air flow resistance of the tubing to a minimum. This was important since a high resistance induced lung fatigue in the wearer.
The air flow equalising device was either of the Briggs pattern, a box shaped bellows carried on the back of the wearer, or a corrugated tubular shaped bellows, the Haldane pattern, which connected the mouthpiece to the air tube. On inspiration the bellows contract as air was drawn from them, and air began to flow along the tube, whilst during exhalation the bellows expanded to their normal size and kept the air flowing steadily along the air tube. In this way the air resistance was kept down to about l-l/2" of water gauge, whereas if the air flowed intermittently, at a high rate during inspiration, and then stopped altogether during expiration, the resistance would build up to as much as 10"- ll" of water gauge.

The Antipoys Apparatus. (1) This apparatus comprised head harness, nose clip, vulcanised rubber mouthpiece, rubber disc type inhalation valve, Tissot type exhalation valve, Haldane equaliser device, body belt and air tube with strainer. The Bloman Apparatus. (ii) Was similar to the Antipoys but had, in addition a hand operated rotary blower mounted on a japanned steel case designed to contain the whole apparatus when not in use. See picture

The Briggs Apparatus. (iii) Comprised a Briggs equalising device, with mouthpiece and breathing tubes, inlet valves were mica discs, the outlet valve was of the Tissot types. Air flow depended entirely on the equaliser device as bellows were not permitted for use with this Apparatus. Tube breathing apparatus-made by Siebe, Gorman, Ltd.

Precautions when using short distance tube breathing apparatus.
The approved types were for use over a limited range of forty yards, and this distance was not to be exceeded. Care had to be taken to avoid damaging the breathing tubes, and air supply tube. Bellows had to be operated continuously on the helmet types when in use.
A small bird and a flame safety lamp had to be used and observed continuously at the fresh air end of the tube.
The air supply tubes should be underwater tested at least at six monthly intervals.