Section 24-165. Use of air contaminant detector; use of contaminant recorder; recording of time, duration, concentration and density of air contaminant

(a) Whenever the use of  an  air  contaminant  detector  is  required  by  this code, the air contaminant detector must automatically
  cause both an audible signal sufficiently loud to be heard by  a  person
  of  normal  hearing  twenty feet from the detector and a readily visible
  flashing red light upon the emission of an air contaminant of a  density
  which  appears darker than number one on the standard smoke chart, or of
  an opacity which obscures vision to  a  degree  greater  than  smoke  of
  number one density on the standard smoke chart.
    (b)  The signalling devices of the air contaminant detector shall also
  be located at the principal work location of the person supervising  the
  equipment.
    (c)  If two or more units of equipment are connected to a single flue,
  one air contaminant detector may be used if installed to monitor all  of
  the units.
    (d)  If  the  light  source of a photoelectric type of air contaminant
  detector fails to operate  properly,  the  detector  must  automatically
  cause  an  audible  signal  sufficiently loud to be heard by a person of
  normal hearing twenty feet away from the detector and a readily  visible
  flashing red light which shall continue to operate until manually reset.
    (e)  Whenever  the  use  of an air contaminant recorder is required by
  this code, the air contaminant recorder must:
    (1) continuously produce a record of the time, duration, concentration
  and density of an air contaminant of a density which appears darker than
  number one on the standard smoke chart, or of an opacity which  obscures
  vision to a degree greater than number one; or
    (2)   continuously  produce  a  record  of  the  time,  duration,  and
  concentration of sulfur  dioxide  and  nitrogen  oxides  by  volume  and
  particulate matter by weight.
    (f) Except as provided in section 24-171 of this code, the record made
  by  the  air  contaminant  recorder  shall  be dated and retained on the
  premises where the recorder is located for a period of sixty  days  from
  the last date appearing on the record.