8. The occupier of a slaughterhouse at which a chamber is used shall ensure that—
(a)the chamber and the equipment used for conveying any bird through the gas mixture are designed, constructed and maintained—
(i)so as to avoid injury to any bird; and
(ii)so that once a bird enters into the chamber it is conveyed to the point in the chamber of maximum concentration of the gas mixture within a maximum period of 10 seconds;
(b)the installation has an apparatus which maintains the required concentration by volume of oxygen or carbon dioxide, as appropriate, in the chamber;
(c)the chamber is fitted with devices which—
(i)measure the concentration by volume of oxygen or carbon dioxide in the gas mixture, as appropriate, at the point of maximum concentration;
(ii)when the chamber is in operation, display continuously the concentration by volume of oxygen or carbon dioxide, as appropriate, as a percentage of the total gas mixture at the point of maximum concentration in the chamber; and
(iii)give clearly visible and audible warning signals—
(aa)where the gas mixture used is that mentioned at paragraph 7(2)(a), if the concentration by volume of oxygen rises above 5% for more than 30 seconds; and
(bb)where the gas mixture used is that mentioned at paragraph 7(2)(b), if the concentration by volume of carbon dioxide falls below 25% or rises above 30%;
(d)there is a means of visually monitoring birds which are in the chamber;
(e)there is a means of flushing the chamber with atmospheric air with the minimum delay; and
(f)there is a means of access to any bird in any part of the chamber with the minimum of delay.