TOXIC GAS METERS BASIC INFORMATION AND TUTORIALS

What is a toxic gas meter?


Description and Application.
This analyzer uses an electrochemical voltametric sensor or polarographic cell to provide continuous analyses and electronic recording. In operation, sample gas is drawn through the sensor and absorbed on an electrocatalytic sensing electrode, after passing through a diffusion medium.

An electrochemical reaction generates an electric current directly proportional to the gas concentration. The sample concentration is displayed directly in parts per million. Since the method of analysis is not absolute, prior calibration against a known standard is required.

Exhaustive tests have shown the method to be linear; thus, calibration at a single concentration, along with checking the zero point, is sufficient.

Types: Sulfur dioxide, hydrogen cyanide, hydrogen chloride, hydrazine, carbon monoxide, hydrogen sulfide, nitrogen oxides, chlorine, and ethylene oxide. These can be combined with combustible gas and oxygen meters.

Calibration. 
Calibrate the direct-reading gas monitor before and after each use in accordance with the manufacturers instructions and with the appropriate calibration gases.

Special Considerations.

• Interference from other gases can be a problem. See manufacturers literature.

• When calibrating under external pressure, the pump must be disconnected from the sensor to avoid sensor damage. If the span gas is directly fed into the instrument from a regulated pressurized cylinder, the flow rate should be set to match the normal sampling rate.

• Due to the high reaction rate of the gas in the sensor, substantially lower flow rates result in lower readings. This high reaction rate makes rapid fall time possible simply by shutting off the pump. Calibration from a sample bag connected to the instrument is the preferred method.

INFRARED ANALYZERS BASIC INFORMATION AND TUTORIALS

What is an Infrared Analyzer?

Description and Applications.
The infrared analyzer is used as a screening tool for a number of gases and vapors and is presently the recommended screening method for substances with no feasible sampling and analytical method.

These analyzers are often factory-programmed to measure many gases and are also user-programmable to measure other gases. A microprocessor automatically controls the spectrometer, averages the measurement signal, and calculates absorbance values.

Analysis results can be displayed either in parts per million (ppm) or absorbance units (AU). The variable path-length gas cell gives the analyzer the capability of measuring concentration levels from below 1 ppm up to percent levels.

Some typical screening applications are:

• Carbon monoxide and carbon dioxide, especially useful for indoor air assessments;
• Anesthetic gases including, e.g., nitrous oxide, halothane, enflurane, penthrane, and isoflurane;
• Ethylene oxide; and
• Fumigants including e.g. ethylene dibromide, chloropicrin, and methyl bromide.

Calibration.
The analyzer and any strip-chart recorder should be calibrated before and after each use in accordance with the manufacturer's instructions.

Special Considerations. 
The infrared analyzer may be only semispecific for sampling some gases and vapors because of interference by other chemicals with similar absorption wavelengths.

Maintenance. 
No field maintenance of this device should be attempted except items specifically detailed in the instruction book such as filter replacements and battery charging.

NEW EMPLOYEE SAFETY ORIENTATION TUTORIALS AND TIPS

For employers with a safety manager, the manager can conduct the classroom part of orientation/training, prepare all the training materials (handouts, forms, checklists, lesson plan, etc.), conduct the employee evaluation, and maintain all documentation. The facility supervisor(s) can conduct the on-the-job training and observation, and determine when the employee is çéady for the evaluation.

For employers or departments without a safety manager, the company safety committee can share responsibilities for conducting the job hazard analyses and the training program. The safety committee can put together the orientation/training materials, conduct the "classroom" training, and keep records. The department where employees will work can conduct the hands-on training.

During the orientation period, introduce new workers to all the basic safety information that applies to their work areas, such as:

• General hazards in the work area;
• Specific hazards involved in each task the employee performs;
• Hazards associated with other areas of the facility;
• Company safety policies and work rules;
• Proper safety practices and procedures to prevent accidents;
• The location of emergency equipment such as fire extinguishers, eyewash stations, first-aid supplies, etc.;
• Smoking regulations and designated smoking areas;
• Emergency evacuation procedures and routes;
• Who to talk to about safety questions, problems, etc.;
• What to do if there is an accident or injury;
• How to report emergencies, accidents, and near misses;
• How to select, use, and care for personal protective equipment;
• Safe housekeeping rules;
• Facility security procedures and systems;
• How to use tools and equipment safely;
• Safe lifting techniques and materials-handling procedures; and
• Safe methods for handling, using, or storing hazardous materials and the location of material safety data sheets.

Orientation programs can be updated and refined by reviewing accident near-miss reports. Near-miss reports offered early warning signs of new or recurrent hazards in the workplace that must be corrected before someone gets hurt or equipment is damaged.

An evaluation of illness and injury reports are also a catalyst for changes in safety orientation and training programs. Orientation can involve several ley els of new employee involvement, from awareness information to formal training programs.

Awareness orientation/training informs employees about a potential hazard in the workplace and their role in responding to the hazard, even though they are not directly exposed to the hazard. For example, "affected" employees can be told about locks and tags for electrical systems without being trained how to implement the lockout/tagout program.

It is useful to rely on a checklist to ensure that appropriate safety orientation is provided to new workers. These checklists should be modified to fit the needs of the organization or site.