Question 1 of 7: Personal Protective Equipment — Eyes/Face and Respiratory
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Notes on this paper
National Exams — December 2019 — 11-CS-2 Engineering in Society: Health and Safety. Closed book. Do any five of the seven questions (each 10 marks). Full essay-type answers are expected; sketches may support the explanations. Complete answers to all seven questions follow.
Note on the reference charts. Questions 2 and 7 depend on the two attachment pages: page 6 is the Brauer/Dalziel chart of the effects of 60 Hz AC current on a 150 lb (68 kg) man, and page 7 is the Fine risk-assessment nomograph. The nomograph prints only the qualitative descriptors (no numbers appear on its Likelihood, Exposure or Consequence axes), so the scale points used below (Likelihood 10 / 6 / 3 / 1 / 0.5 / 0.1, Exposure 10 / 6 / 3 / 2 / 1 / 0.5, Consequence 100 / 40 / 15 / 7 / 3 / 1) are the standard Fine–Kinney values that the chart's own axis spacing reproduces. Selecting a descriptor for each activity is a matter of judgement; the choices are stated explicitly below and reasonable justified alternatives are equally acceptable, as the paper's Note 8 permits.
Question 1: Personal Protective Equipment — Eyes/Face and Respiratory (10 marks)
Safety glasses (with side shields) — for impact from flying particles in general machining, chipping and grinding.
Goggles — sealed against dust or chemical splash; for dusty work, and for handling liquids/chemicals (splash goggles).
Face shield — full-face protection against flying debris and splash (worn over glasses/goggles); for grinding, and chemical decanting.
Welding helmet / goggles with shaded filters — against the intense optical (UV/IR) radiation and sparks of welding and cutting; the shade number is matched to the process/current.
Laser eyewear — wavelength-specific filters where lasers are used.
(b) Respiratory Protection
Air-purifying respirators — filter the contaminant from the air, for adequate-oxygen atmospheres:
Particulate filtering facepieces (N95-type) — for nuisance/fine dusts (sanding, sweeping).
Half- or full-face respirators with particulate filters and/or chemical cartridges — for fumes, mists and vapours (welding fume, painting, solvent vapour).
Powered air-purifying respirators (PAPR) — for higher comfort/protection.
Atmosphere-supplying respirators — supply clean air independently, required for oxygen-deficient, IDLH or unknown atmospheres (confined spaces, high toxic concentrations): supplied-air (airline) respirators and self-contained breathing apparatus (SCBA).
Selection depends on the contaminant, its concentration, the oxygen level and the required protection factor; air-purifying types must never be used where oxygen is deficient or the atmosphere is unknown. Respirators require fit testing.
