6. No person may stun a pig by exposure to gas unless the gas stunner provided for that purpose, including equipment used for conveying the pig through the gas mixture, is—
(a)designed, constructed and maintained so as to—
(i)avoid injury to the pig; and
(ii)avoid compression of the chest of the pig; and
(b)equipped to—
(i)measure and continuously display the required gas concentration (set out in Table 3 of Chapter I of Annex I); and
(ii)give clearly visible and audible warning signals if the concentration of gas falls below the required level in Table 3 of Chapter I of Annex I.