OCCUPATIONAL NOISE STANDARD ALLOWED LEVEL FOR SAFETY BASIC INFORMATION

NOISE STANDARD IN THE WORKPLACE
What is the Allowable Levels of Exposure for Noise in Workplace?

Protection against the effects of noise exposure shall be provided when the sound levels exceed those shown in Table 2.3 when measured on the A scale of a standard sound level meter at slow response.

1. When the daily noise exposure is composed of two or more periods of noise exposure of different levels, their combined effect should be considered, rather than the individual effect of each. If the sum of the following fractions:

C(l)/T(l) + C(2)/T(2) C(n)/T(n) exceeds unity, then, the mixed exposure should be considered to exceed the limit value. Cn indicates the total time of exposure at a specified noise level, and Tn indicates the total time of exposure permitted at that level. Exposure to impulsive or impact noise should not exceed 140 dB peak sound pressure level.

When noise levels are determined by octave band analysis, the equivalent A-weighted sound level may be determined as follows.

When employees are subjected to sound exceeding those listed in Table 2.3, feasible administrative or engineering controls shall be utilized. If such controls fail to reduce sound levels within the levels of Table 2.3, personal protective equipment shall be provided and used to reduce sound levels within the levels of the table.

If the variations in noise level involve maxima at intervals of 1 second or less, it is to be considered continuous.

COMBUSTIBLE GAS METERS BASIC INFORMATION AND TUTORIALS

COMBUSTIBLE GAS METERS FOR SAFETY ENGINEERING
What Are Combustible Gas Meters?



These meters use elements which are made of various materials such as platinum or palladium as an oxidizing catalyst. The element is one leg of a Wheatstone bridge circuit. These meters measure gas concentration as a percentage of the lower explosive limit of the calibrated gas.

The oxygen meter displays the concentration of oxygen in percent by volume measured with a galvanic cell. Other electrochemical sensors are available to measure carbon monoxide, hydrogen sulfide, and other toxic gases. Some units have an audible alarm that warns of low oxygen levels or malfunction.

Calibration of Combustible Gas Meters 
Before using the monitor each day, calibrate the instrument to a known concentration of combustible gas (usually methane) equivalent to 25%-50% LEL full-scale concentration.

The monitor must be calibrated to the altitude at which it will be used. Changes in total atmospheric pressure from changes in altitude will influence the instrument's measurement of the air's oxygen content. The unit's instruction manual provides additional details on calibration of sensors.

Special Considerations.
• Silicone compound vapors, leaded gasoline, and sulfur compounds will cause desensitization of the combustible sensor and produce erroneous (low) readings.

• High relative humidity (90%-100%) causes hydroxylation, which reduces sensitivity and causes erratic behavior including inability to calibrate.

• Oxygen deficiency or enrichment such as in steam or inert atmospheres will cause erroneous readings for combustible gases.

• In drying ovens or unusually hot locations, solvent vapors with high boiling points may condense in the sampling lines and produce erroneous (low) readings.

• High concentrations of chlorinated hydrocarbons such as trichloroethylene or acid gases such as sulfur dioxide will depress the meter reading in the presence of a high concentration of combustible gas.

• High-molecular-weight alcohols can burn out the meters filaments.

• If the flash point is greater than the ambient temperature, an erroneous (low) concentration will be indicated.

If the closed vessel is then heated by welding or cutting, the vapors will increase and the atmosphere
may become explosive.

• For gases and vapors other than those for which a device was calibrated, users should consult the manufacturer's instructions and correction curves.

Maintenance of Combustible Gas Meters
The instrument requires no short-term maintenance other than regular calibration and recharging of batteries. Use a soft cloth to wipe dirt, oil, moisture, or foreign material from the instrument. Check the bridge sensors periodically, at least every six months, for proper functioning.

A thermal combustion-oxygen sensor uses electrochemical cells to measure combustible gases and
oxygen. It is not widely used in the area offices.

PORTABLE FIRE EXTINGUISHER SAFETY TIPS BASIC INFORMATION AND TUTORIALS

SAFETY TIPS ON THE USE OF PORTABLE FIRE EXTINGUISHERS



A portable fire extinguisher can save lives and property by putting out a small fire or containing it until the fire department arrives; but portable extinguishers have limitations. Because fire grows and spreads so rapidly, the number one priority for residents is to get out safely.

Safety tips
Use a portable fire extinguisher when the fire is confined to a small area, such as a wastebasket, and is not growing; everyone has exited the building; the fire department has been called or is being called; and the room is not filled with smoke.

To operate a fire extinguisher, remember the word PASS:
 - Pull the pin. Hold the extinguisher with the nozzle pointing away from you,  and release the locking mechanism.
 - Aim low. Point the extinguisher at the base of the fire.
 - Squeeze the lever slowly and evenly.
 - Sweep the nozzle from side-to-side.

For the home, select a multi-purpose extinguisher (can be used on all types of home fires) that is large enough to put out a small fire, but not so heavy as to be difficult to handle.

Choose a fire extinguisher that carries the label of an independent testing laboratory.

Read the instructions that come with the fire extinguisher and become familiar with its parts and operation before a fire breaks out.

Install fire extinguishers close to an exit and keep your back to a clear exit when you use the
device so you can make an easy escape if the fire cannot be controlled. If the room fills with smoke, leave immediately.

Know when to go.
Fire extinguishers are one element of a fire response plan, but the primary element is safe escape. Every household should have a home fire escape plan and working smoke alarms.