Gas Risk ManagementGas Risk Management

Sierra Monitor and Rep Firm Welcome:

ABC Engineering

Gas Risk ManagementGas Risk Management

Introduction

Gas Risk Management

Was this caused by someone not paying attention?

Gas Risk Management

Did some piece of equipment or instrumentation fail?

Gas Risk Management

Did someone not follow procedure?

Gas Risk Management

Could a properly functioning safety system have prevented the disaster?

Gas Risk Management

• Explanation of hazardous gases

• Characteristics of common toxic gases

• Sensor Technology

• Portable and Fixed systems

• Placement of fixed sensors

• Elements of risk reduction

• Overview of available equipment

• Resources and reference

• Applications and usage

Gas Risk ManagementGas Risk Management

Hazardous Gases

Hazardous Gases

• Combustible Gases– Explosion or fire hazard– Must maintain concentration below lower explosive limit (LEL)

• Toxic Gases– Hazardous to human health and safety– Employee exposure must be limited

• Oxygen Displacing Gases– Indirect human health hazard– Deficiency of breathing Oxygen

Combustible Gases

• Lower Explosive Limit (LEL)– Also Lower Flammable Limit (LFL)

– What does it mean?

– % Volume vs. % LEL

• ASTM E681 Standard– Benchmark test to determine LEL

– Tested in Air with 20.9 % Oxygen

Combustible Gases

Too Rich forCombustion

Will SupportCombustion

Too Lean forCombustion

Upper Explosive LimitU.E.L.

Lower Explosive Limit100 % L.E.L.

100%

0%

CO

NC

EN

TR

AT

ION

(% G

as in

Air

)100% LEL Methane = 5% by volume

Combustible GasesC

ON

CE

NT

RA

TIO

N(%

Gas

in A

ir)

100%

0%5%

15%

0%100% LELUEL

Methane

CO

NC

EN

TR

AT

ION

(% G

as in

Air

)

100%

1.5%7.8%

100% LELUEL

PentaneThe flammability

of many gases lies in a very limited range

The LEL differs depending upon the type of gas

Combustible Gases

Combustion Requires• Fuel Source

• Oxygen or Air

• Ignition Source

Combustible Gases

• Possible Ignition Sources– Static Electricity Discharge– Open Flames– Hot Surfaces– Mechanical Friction– Electrical Arc or Spark– Two Way Radio Transmitter– Tools and Test Equipment

Toxic GasesHazard to Human Health and Life Safety

PPM = Parts Per Million

• 1% by volume = 10,000 ppm

• 1 ppm = .0001% by volume

• 1 millionth of the width of the U.S. is 12 feet

Toxic Gases

• Permissible Exposure Limit (PEL)– Time Weighted Average (TWA)

– Short Term Exposure Limit (STEL)

• Immediate Danger to Life and Health (IDLH)

• Relative Gas Density– RGasD Air = 1.0

– Lighter than air, Below 1.0

– Heavier than air, Above 1.0

Carbon Monoxide HazardConc. of CO in Air Toxic Symptoms

100 ppm Fatigue and feeling of being tired

400 ppm Headache within 1-2 hrs., widespread in 2.5 - 3.5 hrs.

500 ppm Dizziness, nausea, convulsions within 45 min.

1,600 ppm Headache, dizziness, nausea within 20 min. Death in 2 hours.

3,200 ppm Headache, nausea within 5-10 min. Death within 30 min.

6,400 ppm Headache, dizziness within 1-2 min. Death within 10-15 min.

12,800 ppm Death within 1-3 minutes.

Carbon Monoxide Hazard

• OSHA General Industrial Safety Order for Carbon Monoxide– Permissible Exposure Limit

(Max. 8 hr. TWA) = 50 ppm

– Short Term Excursion Limit (STEL) = 200 ppm for 15 min/8 hrs

– IDLH = 1200 ppm

– RGasD = 0.97

Chlorine HazardConc. of Cl2 in Air Toxic Symptoms

0.1 ppm Minimum concentration detectable by odor3 ppm Difficulty breathing eye and throat irritation10 ppm Causes serious throat irritation, smarting of eyes30 ppm Coughing, more severe throat irritation, general feeling of

discomfort in the chest40 ppm Respiratory reflexes, coughing, burning of eyes, nausea,

vomiting. Possible death within 30 minutes100 ppm Death within a few breaths

Uses: Water purification, sanitation of industrial wastes, swimming pools, bleaching of pulp and textiles, manufacture of various chemical compounds

Chlorine Hazard

• OSHA General Industrial Safety Order for Chlorine– Permissible Exposure Limit

(Max. 8 hr. TWA) = 0.5 ppm

– Short Term Excursion Limit (STEL) =1 ppm for 15 min/8 hrs

– IDLH = 10 ppm

– RGasD = 2.47

Hydrogen Sulfide HazardConc. of H2S in Air Toxic Symptoms

1 ppm Odor detected, irritation of respiratory tract

10 ppm Allowable for 8 hours exposure (OSHA)

20 ppm Protective equipment is necessary

100 ppm Smell killed in 5 to 15 minutes. May burn

eyes and throat; coughing

500 ppm Respiratory disturbances in 2 to 15 minutes.Coughing, collapse & unconsciousness

1,000 ppm Immediate unconsciousness. Brain damage may result unless rescued promptly. Death in 3 to 5 minutes.

Hydrogen Sulfide Hazard

• OSHA General Industrial Safety Order for Hydrogen Sulfide– Permissible Exposure Limit

(Max. 8 hr. TWA) = 10 ppm– Short Term Excursion Limit (STEL) = 15 ppm for 10 min/8 hrs

– IDLH = 100 ppm

– RGasD = 1.19

Ammonia HazardConc. of NH3 in Air Toxic Symptoms

2 ppm First perceptible odor40 ppm Slight eye and throat irritation100 ppm Acute Irritation of eyes and nasal passages400 ppm Severe irritation of throat, nose, upper respiratory tract700 ppm Severe eye irritation1700 ppm Serious coughing, bronchial spasms, death within 30 min.5000 ppm Serious edema, strangulation, asphyxia, death immediate

Uses: Refrigerant gas, used in soil fertilization, ammoniate fertilizers. Used in metal treating and for extraction of metals from ores. Used as a neutralizing agent of acids in oil and in the manufacture of various chemical compounds. Also used to purify municipal water supplies.

Ammonia Hazard

• OSHA General Industrial Safety Order for Ammonia– Permissible Exposure Limit

(Max. 8 hr. TWA) = 25 ppm

– Short Term Excursion Limit (STEL) = 35 ppm for 15 min/8 hrs

– IDLH = 300 ppm

– RGasD = 0.60

Oxygen Deficiency HazardOxygen Content Symptoms Developed

20.9% Normal Oxygen concentration in air

15 - 19% Decreased ability to work strenuously.

May impair coordination

12 - 14% Respiration increases in exertion, pulse up, impaired coordination, perception & judgment

8 - 10% Mental failure, fainting, unconsciousness, blueness of lips, nausea & vomiting

6 - 8% 8 minutes, 100% fatal; 6 minutes, 50% fatal,

4 - 5 minutes, recovery with treatment

4 - 6% Coma in 40 seconds, convulsions, respiration ceases, death

Oxygen Deficiency Hazard

• Industry Guidelines for Oxygen Deficiency– Breathing gear required below 19.5% and above

23.5% Oxygen content in air

– Confined Space permit procedures may need be followed in some areas

Gas Risk ManagementGas Risk Management

Gas Sensor Technology

Sensor Technology

• Catalytic Bead

• Infrared

• Electrochemical

• Semiconductor

Catalytic Bead

• No Temperature or Humidity Effect

• Silicone and Sulfide Resistant

• 0-100% L.E.L. Scale

• Responds to All Combustible Gases

• Wheatstone Bridge

Catalytic BeadWheatstone Bridge

DCSupply

Output

Detector

Compensator

Infrared

• Methane or Propane• Carbon Dioxide• Accurate & Stable• Large Measurement

Range• Low Maintenance

Sample Cell

Detector Source

Electrochemical• Current Generating

Electrolytic Reaction

• High sensitivity for PPM levels of Toxic Gas

• Specificity to Gas of Interest

• Percent Volume for Oxygen Measurement

Electrolyte

Diffusion Point

Electrodes

Semiconductor (Solid State)

• Long Life Sensor

• Semiconductor Resistive Film

• PPM Range

• High Sensitivity

• Poor Selectivity

• Non-Linear Response

Nobel Metal WireSensor

Heater Coil

Detection Techniques

Combustible Catalytic bead, Semiconductor, Infrared

Oxygen Electrochemical

Toxic Gases Semiconductor, Electrochemical, Infrared

Gas Risk Management

• Explanation of hazardous gases

• Characteristics of common toxic gases

• Sensor Technology

• Portable and Fixed systems

• Placement of fixed sensors

• Elements of risk reduction

• Overview of available equipment

• Resources and reference

• Applications and usage

Portables vs. Fixed

• Use Portables– When area is not normally occupied– When area has no power or infrastructure– When temporary work crew must maintain their own safety

equipment– When fixed system is down for maintenance

• Use of Fixed Systems– When area is regularly occupied– When automatic systems must react to a hazardous gas

condition – When insurance or regulatory issues require it– When risk assessment concludes that area must be monitored

continuously 24/7

Portable Devices• Battery Powered

• Can be moved from area to area

• Monitor is attached to the individual who is performing the work

• Prone to damage

• Should be calibrated before every use

Permanent Fixed Installations

SCADA

Calibration & Validation• Factory Mutual (FM) requires that

all approved sensors be calibrated periodically

• Sensor must be exposed to live gas standard to validate performance

• Regular calibration compensates for environmental changes

• Records must be maintained to meet OSHA Due Diligence requirements

• Calibration gas must be certified as primary gas standard

Gas Risk ManagementGas Risk Management

Gas Sensor Placement

Gas Sensor Placement

• Use engineering judgement

• Consider:– Probability of gas leak

– Quantity of gas that could leak

– Environmental conditions

– Dilution rates and convection currents

– Density of gas

– Interfering gases

Gas Sensor Placement

• Place sensors close to possible gas source

• Place sensors in areas where gas might accumulate

• Place toxic gas and oxygen deficiency sensors in the “breathing zone”

• Consider accessibility and maintenance issues

Gas Weight in Relation to Air

• Ammonia Lighter• Butane Heavier• Carbon Dioxide Heavier• Carbon Monoxide Slightly Lighter• Methane Lighter• Chlorine Heavier• Ethane Slightly Heavier• Ethylene Slightly Lighter• Heptane Heavier• Hydrogen Lighter

Gas Weight in Relation to Air

• Hydrogen Chloride Heavier• Hydrogen Cyanide Lighter• Hydrogen Sulfide Heavier• Methyl Alcohol Heavier• Nitric Oxide Slightly Heavier• Nitrogen Dioxide Heavier• Pentane Heavier• Propane Heavier• Sulfur Dioxide Heavier• Toluene Heavier

Gas Risk ManagementGas Risk Management

Risk Reduction

Responsible Risk Management

• Identify hazards...

• Assess risk of hazardous event...

• Comply with laws, insurance requirements...

• Consider liability, financial risks...

Develop and implement a strategy of comprehensive event response and prudent risk management

Risk Reduction

InsuranceRequirements

CompanyPhilosophyRisk to

Personnel

Risk toEnvironment

Risk toFacility

Hazard Identification &Assessment

Control SystemCapability/Cost

Tradeoffs

Laws &Regulations

Decision,Control Strategy,System Selection

FinancialRisks

Liability

Risk Reduction

Proper Equipment Selection

• Portable systems– Minimal risk of hazardous event– Battery powered, must be carried on person

• Gas Alarm Monitors– Minimal risk of hazardous event– Simple alarm alert, relay output

• Analog Monitors– Moderate risk in defined location– Continuous display, warning and high alarms, limited

diagnostics

Proper Equipment Selection

Gas Alarm Monitors/Systems

Analog Monitors (Single Point)

Distributed Digital Systems (Multi-Point)

Multi-Point Systems

Single Point SystemsGas Alarm Systems

Proper Equipment Selection

Risk Management Systems– Constant risk of hazardous event, defined areas or

facility-wide

– Distributed intelligence for local control and remote monitoring

– Comprehensive event response

– Configurable alarm logic

– Extensive calibration, diagnostic capabilities

– Documentation of due diligence

Sentry - Basic Configuration

110 VACor

220 VAC

12 - 28 VDC

Low Alarm

High Alarm

Trouble

RS232 SerialOutput to

Printer

Resources & Reference

• ANSI/NFPA #325 Guide to fire hazard properties of flammable liquids, gases and volatile solids

• ANSI/NFPA #820 Fire protection in wastewater treatment and collection facilities

• NIOSH Guide to chemical hazards

• OSHA Guide for confined space hazards

Markets - Gas Detection

• Water/Wastewater Treatment Plants

• Chemical/Petrochemical Plants

• Landfills & Solid Waste

• Alternate Fueled Vehicles

• Food & Drug

• Parking Garages

• Gas/Oil Operations

• Pulp & Paper

Water/Wastewater Treatment• Pumping Stations

– Combustible gases, H2S, O2

• Influent/Barscreen Rooms– Combustible gas, O2

• Grit Chamber & Wet Wells– Combustibles, O2, H2S

• Digester– Combustible gas, HCombustible gas, H22SS

• Furnace Room– Combustible gas, COCombustible gas, CO

• Disinfection/ Dechlorination– ClCl22, SO, SO22, NH, NH33

Chemical/Petrochemical Plants• Pipelines & compressor

stations– Combustible gas, H2S, flame

• Laboratories– Toxic gases, O2 deficiency

• Railroad/truck loading stations– Combustibles, toxics, flame

• Storage tanks– Combustibles, flame

Gas/Oil Operations• Well site perimeters

– Combustible gas, H2S

• Sweetening plants, sour gas wells — H2S

• Pipelines & compressor stations– Combustibles, toxics, flame

• Drilling operations– Combustible gas, H2S, oxygen

deficiency, flame

• Combustible gas leaks

Remote Site Monitoring

• Modbus RTU serial communication link from Sentry interfaces to a FieldServer WebServer

• WebServer uses Sentry data to build dynamic browser pages

• Browser pages may be viewed over LAN, WAN or Internet

RS-232Modbus

Sentry Digital Bus Ethernet

I nternet

Sentry WebServer• The Main screen ranges from the default layout of a

single Sentry system to custom graphics that can include a photo or drawing of the building with buttons to specific zones

Default Custom

Review & Discussion

Sierra Monitor Corporationwww.sierramonitor.com

800-72-SIERRA

800-727-4377

FieldServer Technologieswww.fieldserver.com

888 509-1970