The following gas detector tubes are available for direct reading of concentrations of the toxic gas hydrogen sulfide
| Tube | Concentration |
| 4HT | 1-40% |
| 4HH | 0.1-4.0% |
| 4H | 10-3200 ppm |
| 4M | 12.5-500 ppm |
| 4L | 1-240 ppm |
| 4LL | 0.25-60 ppm |
Which of these tubes would be satisfactory for detecting OSHA specified ceiling concentration for hydrogen sulfide? Of the satisfactory tubes, which ne tests the narrowest range of concentrations?
- A process engineer proposes a new solvent that will reduce the quantities required by the process and significantly reduce the quantities of solvent vapors released into the air inside the pant. The new solvent is perchloroethylene, and it is expected to reduce the solvent vapors absorbed into the plant by 20% by volume as compared to old solvent? (Stoddard solvent. You are called in as a Certified Safety Professional to evaluate the proposed change to the process. Do you support the process change? Explain your position
For these two questions, you can refer to the Appendix A of the book.
- A glue making process releases ethylene glycol that becomes generally diluted and intersped through the plant atmosphere. The rate of release is 2.4 cubic feet per hour vapor volume at standard temperature and pressure. The plant dilution system is of general dilution type with makeup air being suppled through windows and doors throughout the plant area? The plant area is 12,000 square feet and the average ceiling height is 16 feet. The problem is to specify the capacity of the general ventilation system required to maintain a steady-state condition throughout this process area that protects against both health and safety hazards due to ethylene glycol. For your information in performing calculations, the following data is provided.
Ethylene glycol
- Molecular weight : 62.1
- Boiling point 197.5 °C
- LEL: 3.2%
- Firepoint -13 °C
- Flashpoint: 232 °F
- Autoignition temperature: 752 °F
- Vapor pressure: 0.05 mm at 20 °C
- PEL: 50 ppm (ceiling)
- How much exhaust ventilation (in cubic feet per hour, general diulution tpe) is required to maintain safety hazards below explosive levels?
- How much exhaust ventilation (in cubic feet per hour, general dilution type) is required to maintain health hazards below OSHA-specified action levels?
- How many plant area room changes would be the level of ventilation calculated in part (b) present?
- A worker exposure to noise in a given plant is measured, resulting in the following readings for various time periods during 8-hour shift?
8:00 A.M.-9.00 AM 86 dBA
9:00 A.M.-11 A.M. 84 dBA
11 a.m.-12 noon 81 dBA
12 noon-1:00 P.M. 101 dBA
1:00 P.M-4:00 P.M. 75 Dba
- Perform computations to determine whether maximum PELs have been exceeded based on TWA calculations.
- Have the ALs have been exceeded?
- Given the noise exposure just described, would the employer be required to furnish hearing protectors?
- Would employees be required to use the hearing protectors?
- Suppose the engineering control could be devised that could cut the noise level (sound pressure level) in half either in the morning or in the afternoon, but not both. Which would you select? Why?
- A full revolution press with two engagement points on the flywheel has two hand palm buttons installed at a distance of 16 inches from the point of operation. Calculate the minimum flywheel speed that will permit this press in compliance with standards. Explain why a slower flywheel would be more dangerous.
- A hospital administrator wants an estimate of X-ray idle time that has a 95.5 percent confidence of being within 4 percent of the actual percentage. Previous analysis indicates that on the average X-ray machine is busy 25% of the time. What sample size should be used?
- Please provide answers on the following questions written outside of lectric panel.
- What is Level 0 Protective clothing and PPE?
- What is shock hazard?
- What is arc flash hazard?
- What is arc flash boundary?
- What is 208 VAC?
- What is NFPA-70E?
- What is HRC level?
- What type of general safety precautions you need to take while working around electric panels?
