PH helmet

Fig. 1.7 The PH helmet (left) and the PHG helmet (right), both reproduced with permission from Porton Down.

Fig. 1.10 Sentry in a front line trench, Salonika, wearing a PH helmet (reprodueed with permission from the Imperial War Museum).

The historical link between the use of HMT to alleviate or prevent the effects of phosgene is a long one. In designing respirators to defend against phosgene during WWI, a range of compounds was examined. For example, soda lime (a mixture of sodium hydroxide and calcium hydroxide) proved effective, while phenol and sodium phe-nolate were also effective and British Phenolate Helmet (P Helmet) was first used on December 15, 1915. This was followed by the Phenolate Hexamine Helmet (PH Helmet) from early 1916 onwards. The PH Helmets comprised a flannel sack which had been dipped in a mixture of... 

Fig. 3-4. Warfare in the chemical age. (a) British soldiers at the Battle of the Somme appear to be wearing PH helmets in this photograph dated July 1916. (b) The PH helmet was an improved version of the earlier hypo and P helmets in which air was inhaled and exhaled through the fabric. The PH helmet incorporated an expiratory valve, and the cloth was impregnated with chemicals designed to destroy phosgene (the active agent was hexamethylenetetramine). This protective mask was stiflingly hot, and prolonged wear resulted in car-...

Fig. 3.14 Square-wave voltammograms of PlGEs modified with sample Cl-12 from abronze mon-tefortino helmet from the Gabriel river valley (Kehn and Ikalesken period) in the Valencian region of Requena, dating back to the Second Iron Age. Electrolyte 0.50 M potassium phosphate buffer, pH 7.0. Potential scan initiated at +650 mV in the negative direction. Potential step increment 4 mV square wave amplitude 25 mV frequency 5 Hz...

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