This publication is intended to serve as a guideline for the use of Macurco products. It is not to be considered all-inclusive, nor is it intended to replace the policy and procedures for any facility. If there are any doubts about the applicability of the equipment to your situation, consult an industrial hygienist or call Macurco Technical Service at 1-877-367-7891.
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Industry Overview
A building's mechanical system is the heartbeat of the heating, ventilation, and air conditioning systems. These areas include utility plants, boiler and chiller rooms, mechanical or electrical rooms, and fuel rooms. Natural gas is a flammable gas mainly composed of methane, with the remaining amount consisting of a mixture of other gases. Natural gas is typically the primary fuel source that is used in a boiler room.
There are two main gas safety concerns within gas boiler rooms. The first concern is a natural gas leak occurring and going undetected. In the event of a gas leak, a build-up can occur, increasing the risk of an explosion and potentially posing significant damage and loss of life. Another concern occurs when natural gas does not combust efficiently and Carbon Monoxide is produced. Carbon Monoxide is a colorless, odorless toxic gas that will go undetected without a proper gas detector; this is driving states to adopt legislation mandating CO detection and activation of shutting down the boiler in the event of a CO build-up. Many states are adopting laws that require the monitoring of these gases that could cause potentially hazardous environments.
Types of Gases Found
Carbon Monoxide (CO)
Carbon Monoxide is often referred to as the "silent killer" because you cannot see it or smell it, so it can cause great harm going undetected. Therefore, a monitor is critical in the detection of CO. Symptoms of Carbon Monoxide poisoning include headaches, dizziness, vomiting, which can often be mistaken for other flu-like illnesses. Carbon Monoxide (CO) is a poisonous gas responsible for hundreds of deaths and numerous non-fatal poisonings each year in the United States. CO poisoning is also the leading cause of unintentional poisoning deaths in the United States.
CO Level in Air and Health Effects
- 0 ppm: Fresh outdoor air.
- 100 ppm: Slight Headache after 1-2 hours.
- 200 ppm: Dizziness, headache, nausea after 2-3 hours.
- 400 ppm: Dizziness, headache, nausea after 1-2 hours / life threatening after 3 hours.
- 800 ppm: Dizziness, headache, nausea after 45 minutes, unconscious after 1 hour, death within 3 hours.
- 1,600 ppm: Dizziness, headache, nausea after 20 minutes, death within 2 hours.
- 3,200 ppm: Dizziness, headache, nausea after 10 minutes, death within 60 minutes.
- 6,400 ppm: Dizziness, headache, nausea after 1-2 minutes, death within 30 minutes.
- 12,800 ppm: Instantaneous effect, death within 3 minutes.
Toxic Gases
Some gases are poisonous and are dangerous to life at very low levels. Some toxic gases have distinct odors (e.g., H₂S, NH₃) and others have no odors at all (e.g., CO). Very low levels inhaled, ingested, or absorbed through the skin pose adverse effects from exposure. Examples include Carbon Monoxide, Nitrogen Dioxide, Ammonia, and Hydrogen Sulfide.
Combustible Gases
Combustible gases can create a fire or explosion risk when the right combination of an ignition source, oxygen, and fuel is present.
Methane (CH₄): Methane is a single carbon alkaline and the main constituent of natural gas (roughly 95%). It is used as a common fuel source in many types of applications. The molecule consists of one carbon atom bonded to four hydrogen atoms.
Propane (C₃H₈): Propane is a three-carbon alkaline produced as a by-product of natural gas processing and petroleum refining. It is used as a fuel source for domestic, industrial, and transportation applications. The molecule consists of three carbon atoms bonded to eight hydrogen atoms.
The minimum concentration of a combustible gas or vapor necessary to support combustion in air is defined as the Lower Explosive Limit (LEL). Below this level, the gas mixture is too "lean" to burn. The maximum concentration of a gas or vapor that will burn in the air is defined as the Upper Explosive Limit (UEL). Above this level, the mixture is too "rich" to burn. The range between the LEL and UEL is known as the flammable range for that gas or vapor. Examples of combustible gases include Methane, Hydrogen, and Propane.
Equipment Selection & Location
Ventilation Considerations
The primary purpose of having ventilated air in a boiler room is to provide combustion air for the boiler to work correctly. Ventilation can also aid in the reduction of a natural gas leak or the accumulation of Carbon Monoxide. Depending on the type of ventilation and air exchanges, this is not a guarantee of safety mitigation. Therefore, a gas detection system is recommended for these types of applications.
Detection System
Each application and installation may differ, but at a minimum, you will want both a Carbon Monoxide detector and the appropriate combustible gas sensor based on the fuel being used.
Macurco CM-6 (24V) / CM-12 (120V) for Carbon Monoxide
- Coverage Area: up to 1,257 sq. ft (Centrally mounted, radius is 15-20 ft).
- Recommended mounting height: 4-6 ft. above the floor.
- Mounting location: Centrally, where air movement is generally good.
- Avoid mounting in a corner.
- Avoid mounting where normal ambient temperature is below -4°F (-20°C) or exceeds 122°F (50°C).
Macurco GD-6 (24V) / GD-12 (120V) for Combustible Gas
- Coverage Area: up to 1,257 sq. ft (Centrally mounted, radius is 15-20 ft).
- Recommended mounting height (target gas-dependent):
- Natural Gas (Methane): roughly 12" below the ceiling.
- Propane: roughly 12" above the floor.
- Mounting location: Centrally, where air movement is generally good.
- Avoid mounting in a corner.
- Avoid mounting where normal ambient temperature is below -4°F (-20°C) or exceeds 122°F (50°C).
Macurco Gas Boiler Controller (GBC-24)
Used with Macurco detectors to shut down boilers or the safety circuit in the presence of gas. It can use up to 4 detectors per controller and shut down up to 8 boilers/appliances with dedicated relays. It provides local audible/visual notification and supports optional external audible/visual notification.
Macurco Horn/Strobes
The Macurco Horn and Strobe are recommended for areas needing distinctive visual or audible signals outside the boiler room to provide additional advance notification in the event of an alarm condition.
Macurco Boiler Control Solution
This solution integrates various components for comprehensive boiler control and safety. It includes:
- Combustible Gas Detector (e.g., Macurco GD-6)
- Carbon Monoxide Detector (e.g., Macurco CM-6)
- Boiler Control Unit (Macurco GBC-24)
- Ventilation System
- Boiler
- Remote Audio/Visual Notification
Example Gas Boiler Controller Layout & Maintenance
Example Gas Boiler Controller Layout
The layout illustrates a typical gas boiler control system. It features a boiler, associated piping, and gas lines. A Macurco Gas Boiler Controller (GBC-24) is centrally located. Detectors are positioned based on the gas type: Methane/Hydrogen (Natural Gas) is mounted 12 inches from the ceiling, Carbon Monoxide is mounted 4-6 feet from the floor (breathing level), and Propane (LP) is mounted 12 inches from the floor. An Audio/Visual Notification unit is located outside the room to alert personnel.
Boiler Control Placement: Placement may vary based on room layout. It should be located out in the open, in a well-accessible and visible area near the main entry/exit door.
Maintenance: Demonstration and Training
Regular maintenance involves inspecting components, equipment installation, and electrical connections for compliance with requirements. It is crucial to test the alarm setpoints of the gas detection system using calibration and test gases, and to verify the sequence of operation. Personnel should be trained on how to adjust, operate, troubleshoot, calibrate, and maintain the gas detection and control systems. Calibration and test kits should be provided with the gas detection system. Calibration and test intervals must comply with the manufacturer's recommendations. If required, a written report should be prepared to record test procedures, results, and corrective actions. This information should also cover requirements for accessories, such as the acceptability of alarm types, signs, and protective equipment. Macurco should perform any repair or replacement of malfunctioning units.
About Macurco Gas Detection
Celebrating 50 years of gas detection, the Macurco product line offers equipment for residential, commercial, and industrial applications. Since 1972, Macurco has been providing detection options for several different gases, including Carbon Monoxide (CO), Nitrogen Dioxide (NO₂), Hydrogen (H₂), Propane (LP), Methane (natural gas), Hydrogen Sulfide (H₂S), Ammonia (NH₃), Oxygen (O₂), Carbon Dioxide (CO₂), and refrigerants.
Headquartered in Sioux Falls, South Dakota, Aerionics manufactures Macurco Gas Detection products. Aerionics strives to provide the highest quality detection, safety, and security solutions to customers worldwide. Whether you are looking for gas detection for a security system, building automation or HVAC system, for personal safety, or for monitoring specific gases in potentially hazardous environments, Macurco has a gas detector to meet your needs.
Gas Detection is All We Do, and We Do It Best.
Visit www.macurco.com for additional product information and training.
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Manufactured by Aerionics, Inc. Sioux Falls, SD
Phone: 1-877-367-7891
Email: info@macurco.com
Website: www.macurco.com
Macurco Gas Detection – Gas Detection, Its what we do.
