CO2 and Oxygen Deficiency Gas Detectors for Safety and Process Gas Monitoring

Experts in Brewery Gas Detection

The brewing of beer is a century's old tradition steeped in malted barley, hops, water, fermentation and special ingredients.

Gas hazards in a modern brewery consist of Carbon Dioxide from fermentation, CO₂ recovery and carbonation processes, Disinfectants for cleaning, water purification or waste stream treatment and sterilization, Ammonia leaks from refrigeration, and gases which are by-products of waste treatment such as Hydrogen Sulfide and Methane, plus the potential for Oxygen deficiency in certain areas.

Carbon dioxide (CO2) gives the fizz to soft drinks and the head on beer. In breweries CO₂ is recovered from fermentation and used for carbonation. High concentrations of CO₂ are toxic and can cause Asphyxiation.  Above 1,000 PPM (0.1%) CO₂ causes drowsiness. Caution: CO₂ is heavier than air and cellar or low lying and enclosed areas may be hazardous. Oxygen deficiency monitoring is recommended. See Table 1. for more gas exposure information.

Gas Action Table

Gas Name (Formula)	NIOSH IDLH	ACGIH TLV	OSHA PEL
Carbon Dioxide (CO2)	4% by vol.	0.5% or 5,000 ppm	0.5% or 5,000 ppm
Oxygen (O2)	<18%	<19.5%	<19.5%
Ammonia (NH3)	300 ppm	25 ppm	50 ppm
Chlorine (Cl2)	10 ppm	0.5 ppm	0.5 ppm
Chlorine Dioxide (ClO2)	5.0 ppm	0.1 ppm	0.1 ppm
Methane (CH4)	Explosive Alarm @ 10-20% and 40-50% LEL
Hydrogen Sulfide (H2S)	100 PPM	10 ppm	10 ppm
Ozone (O3)	5 ppm	0.1 ppm	0.1 ppm
Sulfur Dioxide (SO2)	100 ppm	2 ppm	5 ppm

 

Pure water suitable for brewery use can have a combination of settling, aeration, coagulation, filtration, and sterilization treatments. Ozone or Chlorine may be used in treatment and these must be monitored at the storage or generation and injection points. These gas sensors are usually placed low due to the gas density. See Table 2. for more information.

Process Equipment Cleaning often utilizes sterilization chemicals or gases which are stored in tanks or cylinders with metering or injection pumps. Such an equipment area needs to be treated like confined space with permanent gas monitoring equipment and annunciation.

Brewery wastewater has a high organic content. To minimize the potential impact that it can have on a municipal wastewater treatment system, anaerobic digestion is increasingly being used. This process generates Biogas and allows recovering solids for land application. The Gas may also be recovered and used for steam generation. Water is often re-processed for irrigation and other uses, reducing effluent.

Biogas consists mainly of Methane, CO₂ and H₂S. The presence of Methane means that the area may be hazardous (classified) as Class I, Division 1, Group D in the wet wells and process vessels[5].  This is reduced to Division 2 or unclassified at certain distances from the Biogas equipment or process vents. Methane Sensors are mounted high and the H₂S and Oxygen deficiency sensors are installed in the breathing zone as needed. The exact requirements change with the process type and configuration. See Table 2. for sensor placement.

Ammonia Refrigeration

Ammonia refrigeration is non-polluting and very energy efficient. It's a workhorse for processing and bottling in Dairy, Wineries, Breweries, Juice production, and Soft Drink bottling. However, Ammonia is a toxic, highly reactive and corrosive gas. Spills and releases pose a significant threat to workers from skin contact, inhalation, fire and even explosion.

An Ammonia Refrigeration Monitoring System consists of gas sensors located in strategic areas, with a Central Control Unit for, alarming, ventilation, and shutdown functions.  Compliance with the Process Safety Management regulations[6] requires that the system have local annunciation, supervisory notification, and uninterruptible power or battery back-up.

ANSI/ASHRAE Code 15-2004 requires a gas sensor set to alarm at the Ammonia PEL³ (50 PPM), and insurance companies may dictate emergency ventilation at 150 to 250 PPM, with compressor or complete electrical shutdown at higher levels.  More than one sensor is employed for redundancy, and the Ammonia vent lines and Condensing units are often monitored to detect leaks.

Ammonia sensors are usually placed above or near potential leak sources in the engine room and bottling areas. Personnel safety monitoring is done in the breathing zone near the work areas as required. Caution: Larger Ammonia leaks can form a drifting aerosol which is slow to disperse. See Table 2. for more sensor mounting information. 

Carbonation and Bottling

Carbonation and bottling is an activity that requires CO₂ and Ammonia monitoring. Many brewers include an Oxygen deficiency monitor if the immediate area is occupied by personnel. CO₂ recovery, purification and liquefaction machinery can also fail or leak and produce a hazardous atmosphere. This area should be part of the overall hazard assessment for the facility, with gas monitoring deployed if necessary.

Other Gases

Other gases or vapors may be present in food and beverage operations, such as Ethylene, Sulfur Dioxide, Phosphine, Ethanol and Chlorine Dioxide. These gases should be monitored for compliance with the OSHA Air Contaminant regulations, which are detailed in 29 CFR -1910.1000, Tables Z-1 and Z-2.  Care must be exercised to ensure that installed gas sensors are highly specific and will not cause false alarms by responding to non-target gases.

Gas Detection System Requirements vary somewhat by jurisdiction. The Fire Codes include many safety standards by incorporation or reference. The local Fire Marshall is the authority charged with safety code enforcement. Close communication with local authorities during project design and permitting stages is highly recommended.

Gas	Density	Sensor Mounting
CO2	1.5	Breathing Zone or Lower
O2	1.1	Breathing Zone (4-6 Feet)
NH3	0.6	Breathing Zone and High
Cl2	2.5	Within 6 inches of Floor
ClO2	2.3	Within 6 inches of Floor
CH4	0.6	Within 12 inches of Ceiling
H2S	1.2	Breathing Zone (4-6 Feet)
O3	1.6	Breathing Zone or Lower
SO2	2.3	Near "Potential Leaks" or Breathing Zone

Table 2. Gas Density versus Sensor Placement

OSHA requires a quarterly or semi-annual functional test of gas detection system operation, which is usually performed as part of routine calibration with a known gas standard. This tests the system alarms, annunciation, supervisory notification, and mitigation or shutdown measures and evacuation procedures. Employees should be actively involved as practice for a real event. Outside emergency responders can also be present for familiarization and training.

Gas Detection Solutions

Gas detection solutions must be carefully engineered. Close communication and collaboration with suppliers and installation or integration parties, insures that expectations will be met, problems resolved, personnel trained, routine maintenance planned, and that the system complies with local, State and Federal regulations.

Sensidyne offers comprehensive solutions for gas detection and monitoring inside of breweries and distilleries. Our offering includes systems suitable for facilities from small to large. We look forward to speaking with you regarding your brewery or distillery gas detection application.

 

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 National Institute of Occupational Safety and Health. See http://www.cdc.gov/niosh/npg/npgname-c.html for Chemical Data.
 IDLH: "Immediately Dangerous to Life and Health," A NIOSH value defined as the maximum exposure concentration in the workplace from which one could escape within 30 minutes without any escape-impairing symptoms or any irreversible health effects.
 ACGIH: American Council of Governmental Industrial Hygienists; TLV, Threshold Limit Value, the average concentration in ppm for an 8-hour workday and a 40-hour workweek to which nearly all workers may be repeatedly exposed, day after day, without adverse effects.
 29 CFR 1910.1000, OSHA Table Z1; PEL, Permissible Exposure Limit, expressed as an 8 hour TWA, Time Weighted Average.
NFPA 820, Standard for  Fire Protection in Wastewater Treatment and Collection Facilities
29 CFR, 1910-119A, Process Safety Management; 40 CFR, 68, Subpart G., Risk Management Plan
 NFPA 1, The Uniform Fire Code; The 2006 International Fire Code
 Density is relative to Air of 1.0