Sensors should be located near the floor for gases or vapors three or four times heavier than air.
Gas detectors should be installed in the room where a gas escape is most likely to occur. Natural gas detectors should be installed above the level of a possible gas escape and near the ceiling (typically < 30 cm (12 inches) from the ceiling), in a place where air movements are not impeded by furniture and furnishings.
Honeywell, a leading gas detector manufacturer, recommends placing your detector higher than all doors and windows and about 6 inches from the ceiling and within about 10 feet of the appliance.
Thus, personal gas detectors should be worn in a worker's breathing zone, which OSHA defines as “a hemisphere forward of the shoulders within a radius of approximately six to nine inches.” A collar, lapel, or breast pocket usually meets those criteria.
Methane gas detectors should therefore be placed near the ceiling, leaving a distance of at least 6 inches from the ceiling, while also avoiding dead air spaces, e.g. corners.
Natural gas is 30% lighter than air. If a leak occurs in an open area, natural gas will easily vent and dissipate into the atmosphere. When enclosed, natural gas will rise to the ceiling and fill the room from top to bottom.
Gas monitors should be kept in a climate-controlled environment. Anything like excessive temperatures, humidity, etc. will quickly damage your sensors inside the unit and greatly shorten their life span. You should also be aware of excessive solvents or dangerous compounds that can cause damage to the sensors as well.
Wear Personal H2S Monitors in the Breathing Zone
The breathing zone is commonly defined as an area downward and forward from the mouth and nose within at most 9 or 10 inches. Remember that this is the optimum location, but detection is never perfect.
Since Ammonia is lighter than air, sensors are normally positioned in the breathing zone, four to six feet above grade, or above the potential leak sources.
Where should H2S monitors be placed? H2S gas monitors should always be worn in the breathing zone, which refers to the nine-inch area around the person's nose and mouth. Many workers will clip the monitor to their hard hat, lapel, or collar.
Natural gas is lighter than air and rapidly dissipates into the air when it is released. When natural gas burns, a high-temperature blue flame is produced and complete combustion takes place producing only water vapor and carbon dioxide.
The Combustible Gas Leak Detector Pen is extremely sensitive, with a detection range of 0 to 100% lower explosive limit. Its low alarm level is 20±5% and 50±10%, with the high alarm level being greater than 50±10%.
LEL & Gas Detection Systems
Fixed LEL detectors are typically installed close to sources of leaks, adjacent to air handler intake vents, or in the ceiling of an enclosed building or room.
Carbon Monoxide and Explosive Gas Detector. The best option to detect harmful gas leaks is a hybrid alarm that detects both carbon monoxide and other explosive gases, such as methane, propane, and other natural gases. The First Alert Combination Explosive Gas and Carbon Monoxide Alarm can be plugged into any AC outlet.
Sulfur or Rotten Egg Smell
A sulfuric or rotten egg smell is the most common and noticeable sign of a natural gas leak. Gas is naturally odorless and colorless; as a precaution utility companies add mercaptan, a harmless chemical, to the system to create the odor.
Toxic gases: Where safe breathing levels are the main concern, sensors should be located in the typical breathing zone, which is 4 to 6 feet from the floor.
Mild to moderate: Nausea, vomiting (emesis), abdominal pain, and burns of the mouth, throat, esophagus, and stomach. Severe: Swelling of the lips, mouth, and voice box (larynx) and severe corrosive damage or burns to the mouth, throat, and stomach.
Ammonia Test Paper
Provides for approximately 750-1000 tests. Product Directions : Tear off a strip of paper, moisten with water and expose to the air. Wait 15 seconds and compare the test strip to the calibrated color chart. The color chart shows readings in ppm of ammonia in air.
While a person cannot see this vapor, ammonia does have a very distinct odor. Most people will recognize or become alarmed by the scent of ammonia in the air. As a natural consequence of prolonged exposure to any odor or compound, however, olfactory fatigue occurs.
Mount sensor near ground level or in a pit, typically 18” to 24” from the floor. As a general rule of thumb, try to mount sensors within 30 feet of potential H2S sources.
Heat and smoke rise, which is why we place smoke alarms high on the wall or ceiling. Carbon monoxide, however, mixes with the air. For this reason, it is preferable to install CO alarms at knee level – the approximate height of a sleeping person's nose and mouth.
CO2 safety monitor sensors should be mounted 12 inches (30.5cm) off the floor. Prior to installing your CO2 (carbon dioxide) safety monitor, it is important to know that proper gas detection placement is just as important as having the device itself.
Only one gas can be measured with each instrument. When heavy dust, steam or fog blocks the laser beam, the system will not be able to take measurements. This is also the case when a person or vehicle blocks the path.
Unlike gas detectors, which are tiedinto a building's system, gas monitors are portable, wireless, and hands-free. They're usually easy to use and light, which makes them ideal for personal usein areas that may have pockets of gas, such as confined spaces.
However, workers must understand the particular hazards of any environment they are entering and take appropriate measures by wearing a confined space monitor. OSHA dictates that the minimum "safe level" of oxygen in a confined space is 19.5%, while the maximum "safe level" of oxygen in a confined space is 23.5%.