In the sulphuring of malt the following recommendations were made by the Austrian inspectors:
During the sulphuring process the room ought not to be entered (for the turning over of the malt). When the sulphur has been burnt, the drying-room must be ventilated from the outside, by opening the windows and letting in cold currents of air, until the sulphur dioxide has completely dispersed, which can be tested by holding a strip of moistened blue litmus paper at the half-opened door. If it does not turn red, turning over of the malt may be proceeded with.
As the sulphuring of hops in hop districts is done in primitive little kilns, in which the hops are spread out on a kind of gridiron and sulphur burnt below in iron pans, development of sulphur dioxide may affect the workers. The following regulations are therefore suggested for work in these kilns:
The rooms in which sulphuring takes place must be airtight, capable of being locked, and provided with arrangements which make it possible to remove the sulphur dioxide fumes before the room is entered. This can usually be done by a strong coke fire, maintained in the chimney place, which creates the necessary draught. If fans are used, it must be remembered that iron is affected and destroyed by acid gases; stoneware fans are therefore advisable.
In the production of vinegar, air escapes laden with acetic acid vapour, alcohol, lower oxidation products of alcohol, aldehyde, acetic ether, &c. Their escape can be avoided if the whole process is carried on in a closed self-acting apparatus with the advantage also that no loss occurs.
In premises for drying agricultural products (fruit, chicory, turnips) the persons employed in the drying-room are exposed to the danger of carbonic oxide poisoning from direct firing.
The following recommendations for work in drying-rooms with direct firing are taken from an Austrian decree of 1901:
The lower drying chambers, in which the real drying process is effected, should be so arranged that the objects dried in them can be removed by means of long-handled implements through a passage shut off from the drying-room. The separation of this passage can be effected by loose tin plates which can be removed as required for the work of turning or removal of the dried products, so that the worker need not come into contact with the gases.
Open fires should be so arranged that if required they can be shut off, by simple arrangements, from the drying-rooms in which the workers are temporarily occupied in carrying in, and turning, the objects to be dried, transferring the partly dried products to hotter hurdles, and emptying them when finished, in such a way that the entrance of combustion gases into the drying chambers can be completely prevented. In order, however, to prevent a back draught, arrangements must be made for simultaneous removal of the gases by pipes connected with a chimney or smoke flue. The places from which the fires are charged should, in addition, be furnished with suitably arranged openings for ventilation leading into the outer air, in order to neutralise, in case of need, any back draught from the furnaces into the rooms.
The windows of the drying chambers should be so arranged as to open both from within and without.