terms critical temperature 2 materials - short.pdf · 2019. 11. 3. · lp gas or lng – the...

10/15/2019

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Copyright © 2017 SPSI Emergency Response Solutions. All rights reserved.

SPSIEmergencyResponseSolutions

Class 2 Materials

Barry Lindley

Slide 2SPSI Emergency Response Solutions

Question

• What is the world's most hazardous material (non-radioactive?)

• Is it a gas, liquid, or solid?


Terms

• Critical Pressure:– Temperature above which a gas cannot

be liquefied by pressure alone


Critical Temperature

• The critical temperature of a substance is the temperature at and above which vapor of the substance cannot be liquefied, no matter how much pressure is applied.


Critical Temperature WaterWater’s Critical Temperature is 374C

25C 100C 374C

Water Vapor


Triple Point• The only temperature

and pressure at which three phases (gas, liquid and solid) in a one-component system can exist in equilibrium

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DOT Definitions


Gas

• Means a material which has a vapor pressure greater than 300 kPa (43.5 psia) at 50°C (122°F) or is completely gaseous at 20°C (68°F) at a standard pressure of 101.3 kPa (14.7 psia).


Non-liquefied Compressed Gas

• A gas, which when packaged under pressure for transportation is entirely gaseous at -50°C (-58°F) with a critical temperature less than or equal to -50°C (- 58°F)


Liquefied Compressed Gas

• A gas, which when packaged under pressure for transportation is partially liquid at temperatures above - 50°C (-58°F), is considered to be a liquefied compressed gas.


Liquefied Compressed GasA liquefied compressed gas is further categorized as follows:

1. High pressure liquefied gas which is a gas with a critical temperature between -50°C (-58°F) and + 65°C (149°F), and

2. Low pressure liquefied gas which is a gas with a critical temperature above + 65°C (149°F).


Compressed Gas In Solution

• A “compressed gas in solution” is a non-liquefied compressed gas which is dissolved in a solvent.– Acetylene in acetone or other solvent is

common

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Cryogenic Liquid

• A “cryogenic liquid” means a refrigerated liquefied gas having a boiling point colder than -90°C (-130° F) at 101.3 kPa (14.7 psi).


Division 2.1

Flammable gas1. Is ignitable at 101.3 kPa (14.7 psia)

when in a mixture of 13 percent or less by volume with air; or

2. Has a flammable range at 101.3 kPa (14.7 psia) with air of at least 12 percent regardless of the lower limit.


Division 2.2• Is a non-flammable, nonpoisonous

compressed gas including compressed gas, liquefied gas, pressurized cryogenic gas, compressed gas in solution, asphyxiant gas and oxidizing gas.

• Which1. Exerts in the packaging a gauge pressure of 200

kPa (29.0 psig/43.8 psia) or greater at 20°C (68°F), is a liquefied gas or is a cryogenic liquid, and

2. Does not meet the definition of Division 2.1 or 2.3.


Division 2.3• Gas poisonous by inhalation. Which

1. Is known to be so toxic to humans as to pose a hazard to health during transportation, or

2. In the absence of adequate data on human toxicity, is presumed to be toxic to humans because when tested on laboratory animals it has an LC50 value of not more than 5000 mL/m3


Hazard ZoneHazard Zone

Inhalation Toxicity

A LC50 less than or equal to 200 ppm.B LC50 greater than 200 ppm and less than or

equal to 1000 ppm.C LC50 greater than 1000 ppm and less than or

equal to 3000 ppm.D LC50 greater than 3000 ppm or less than or

equal to 5000 ppm.


Service Pressure

• The term “service pressure” means the authorized pressure marking on the packaging. – For example, for a cylinder marked

“DOT 3A1800”, the service pressure is 12410 kPa (1800 psig).

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Properties


Gas Properties• Gases can be:

• Flammable• Non-flammable• Oxidizers• Corrosive• Asphyxiants• Poison• Inert• Or a mixture


Basic Safety Rules• The big three:

– Oxidizers: • Must not be used in contact with oils, greases or

other hydrocarbons.– Flammables:

• Must not be exposed to flames, sparks or arcs including static electricity, hot surfaces or oxidizers.

– Non Flammables: • Must not be allowed to displace air in confined

work spaces so that there is insufficient oxygen for breathing.

Continued


Pressure

• By definition all gases have pressure associate with them


Question• What is the pressure

inside the L.P.G cylinder…?– 70 F = 96 PSI– 100 F = 127 PSI– 110 F = 230 PSI– PRD = 250 psi– The regulator reduces

it to around 11 lbs for a grill


High Pressure Gas

• Can cause equip. to fail with explosive force

• When released can diffuse into the atmosphere very rapidly, and an entire room may be thoroughly contaminated within seconds!

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Boyle’s Law• If a gas is held at constant temperature,

the volume is inversely proportional to the pressure.

• Compressing a gas to half of its initial volume doubles its pressure.

• P1V1 = P2V2

1/440 psi 20 psi 10 psi

1/21

Volu

me

in L

iters

PressureSlide 26SPSI Emergency Response Solutions

Charles’s Law• If a gas is held at a constant pressure, the

volume is directly proportional to the absolute temperature.

• Heating the gas to double its original temperature doubles its volume.

• T2V1 = T1V2

1/4100ºK 200ºK 300ºK 400ºK

1/23/41

Volu

me

in L

iters

Temperature


Gay-Lussac’s Law• If a gas is held at a constant volume,

the pressure is directly proportional to the absolute temperature.

• Heating the gas to double its original temperature doubles its pressure.

• T2P1 = T1P2


PVT Relationship• If temperature of a

gas increases in cylinder, volume of cylinder cannot be increased

• Pressure increases and may activate relief valve

• If pressures increase too rapidly, cylinder may rupture

PPT-043-01 28

Slide 29SPSI Emergency Response Solutions Slide 30SPSI Emergency Response Solutions

Liquefied Compressed Gases

• Contents of a liquefied compressed gas cannot be determined by the pressure in the container, and weight of contents must be used

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Compressed Gases

• Use the ideal gas lawPV=nRT

OrP1V1=P2V2


Terms

• Boiling Point: – Temperature when a gas converts from

its liquefied state to vaporous state– Where vapor pressure = atmospheric

pressure


Vapor Density• Specific Gravity Gas• RGasD• 12 lighter than air


Materials Lighter Than Air• Hydrogen (.0696)• Acetylene (.906)• Helium (.138)• Ammonia (.597)• Methane (.554)• Illuminating gas• Carbon monoxide (.967)• Ethylene (.978)

• Hydrogen cyanide (.947)• Nitrogen (.967)• Diborane (.952)• Neon (.696)


TLV-TWA• TLV-TWA (threshold

limit value - time weighted average): – Given in ppm (parts

per million); exposure amount which most people can work in for an eight hour day without suffering harmful effects

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IDLH

• IDLH: Immediately Dangerous to Life and Health– Amounts to which persons should not

be exposed due to their harmful effects; sources for determining these limits will be found on the SDS, as well in various guides, i.e. NIOSH Pocket Guide to Chemical Hazards


LEL

• Lower Explosive Limits (LEL) also known as lower flammable limits (LFL): – Least percentage of a gas, mixed with

the proper proportions of air, whereby having the necessary heat applied, combustion may result


UEL

• Upper Explosive Limits (UEL), also known as upper flammable limits (UFL): – Greatest percentage of a gas, that when

proportioned with air, may permit sustained combustion


Lean Explosive Rich

LEL UELKABOOM

LEL0% 100%

Volume %

Ammonia 12%Methane 5%Hydrogen 4%Hexane 1%

0% 100%


Flammable Limits• Flammable Limits,

also known as the flammable range: % of gas within the LEL and UEL where combustion may occur and be sustained– Shown: Hydrogen

approximated (4-75 percent)

100% Hydrogen

75%

FlammableRange


Ignition Temperature

• Ignition temperature: – Unique to various solids, vapors and

gases, the requisite heat from an open flame source required to ignite materials

• Autoignition temperature: – The temperature required to ignite

materials absent an open flame source

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BLEVE (Boiling Liquid Expanding Vapor Explosion)

• A cylinder or tank is heated• Contents absorb heat and convert to

pressurized vapor• Relief valve activates• Pressure increases beyond the PRV

capacity• Container, thermally stressed, violently

ruptures • If the gas is flammable, the fireball is • devastating


Out Comes


BLEVE• BLEVEs can occur

with refrigerants and cryogens as well as LP gas or LNG– The pressure, volume,

temperature, damage relationship drives the BLEVE


BLEVE• Cylinder exploded

inside a building• Cylinder exploded

outside– May occur with liquefied

petroleum gas (LPG) propane and butane being main components or

– With liquefied natural gas (LNG) of which methane is the largest component


Railroad Tank Car BLEVE• Crescent City, Illinois;

June 21, 1970, 7:30 am

• Train No. 20 derailed involving three tank cars

• BLEVE was 34,000 gallons of Propane

• Emergency planning paid off


Fixed Location BLEVE• 65,000 gallons of

propane at bulk storage location in Canada, 2008

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Inert Gas

• Gas which does not react with other materials such as nitrogen, helium, argon, krypton, neon, xenon


Expansion Rate (or ratio)• Conversion of cubic feet of liquid to

cubic feet of gas– Can result in achieving the LEL or

flammable limits in an inside environment– Can also result in the toxic levels or IDLH

for a gas expressed as percentage by volume or ppm (parts per million)

– Can also result in an asphyxiating atmosphere


Expansion RatioGas Expansion Ratio• Methane 625:1• Propane 270:1• Butane 284:1• Nitrogen 696:1• Oxygen 860:1• Chlorine 444:1


Cryogenic• Heat expands a gas• If we pressurize a gas

while cooling it, we can turn a gas into a liquefied gas

• Further cooling and pressure may convert it to a cryogenic gas

• This increases the amount of product that can be put in a container



Gases


The Gas: Rule #1!

• Know the properties of the materials involved

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How Many

• There are 11 gases as elements• Can you name them?

Air Gases Noble GasesNitrogen (N2) Helium (He) Hydrogen (H2)Oxygen (O2) Neon (Ne) Chlorine (Cl2)Argon (Ar) Argon (Ar) Fluorine (F2)

Krypton (Kr)Xenon (Xe)Radon (Rn)


How Many Regulated DOT

• By name• About 47 flammable gases• About 47 Non flammable gases• About 49 Toxic gases

– 70 have secondary hazards– Does not include mixtures


Think Pyrophoric• Silane• Disilane• Phosphine• Methyl Silane• Diborane• Dlchlorosilane• Arsine• Germane

Think


Think Oxidizer

• Oxidizing potential– O2 = 1– Cl2 = 0.67– Air = 0.21– NF3 = 1.56– ClF3 = OMG


Acid & Alkaline• Shipped as Toxic

– Boron Trichloride– Bromine Trifluoride– Chlorine Trifluoride– Hydrogen Fluoride– Iodine Pentafluoride– Silicon Tetrafluoride– Sulfur Tetrafluoride– Tungsten Hexafluoride

THINKHighly Reactive


Highly Toxic Gases• Arsine• Boron Trichloride• Bromine Trifluoride• Bromine Pentafluoride• Chlorine• Fluorine• Germane• Hydrogen Cyanide• Hydrogen Selenide• Hydrogen Sulfide• Nitric Oxide• Phosgene

Continued

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Properties of Carbon Monoxide

• Odorless, colorless, tasteless, non-irritating gas• Virtually undetectable without specialized

equipment• A natural by-product of incomplete combustion

from equipment burning carbon based fossil fuels such as:– Gasoline– Wood– Coal– Propane– Oil– Methane


Properties of Carbon Monoxide

• Flammable gas– Auto ignition temperature = 1128° F– Lower Explosive Limit 12.5%– Upper Explosive Limit 74%

• Vapor Density of .968– Slightly less than that air– CO will rise with warm air– CO disperses evenly once it cools


Possible Sources of CO

• Attached garages with running automobiles

• Cooking and heating appliances– Improperly vented– Not serviced – Inefficient/improper operation


Health Hazards

• A “silent killer”: CO will kill before its presence is known

• No early warning signs• Displaces O2 in the bloodstream• Victims die from asphyxiation


Health Hazards• Absorbed into the body through

lungs• Transferred to the blood• Combines with hemoglobin to

become carboxyhemoglobin (COHb)• CO poisoning is measured by the %

of COHb in the blood


Carbon Dioxide

CO2 % Max ExposureBy Volume Limit, Minutes

0.5 Indefinite1.0 Indefinite1.5 4802.0 603.0 204.0 105.0 76.0 57.0 Less than 3

A Total Flood carbon dioxide system will displace the breathable oxygen and asphyxiate those inside

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• IDLH 100 ppm• PEL C 20 ppm

50 ppm (10 min max peak)

• IP 10.46 eV• RGasD 1.19• LEL 4.0%• UEL 44.0%

Hydrogen Sulfide


Most Commonyl Used Cryogenics

• Liquid nitrogen (LIN)• Liquid oxygen (LOX)• Liquid argon (LAR)• Liquid carbon dioxide• Liquid hydrogen• Liquid helium• Liquid ethylene• Liquefied natural gas (LNG)• Liquefied petroleum gas (LPG)


Cryogenic Liquid Elements

Krypton -244º FMethane -258º FEthylene -273º FOxygen -297º FArgon -302º FNitrogen -320º FNeon -410º FHydrogen -423º FHelium -452º F

NOTE: Atmospheric gases turn solid at boiling points for neon, hydrogen and helium


Potential Hazards ofCryogenic Liquids

• Frostbite on skin caused by short term exposure to very low temperatures

• Large volumes of gas generated by high expansion of liquid to gas (~800x expansion ratio)

• Flammable gas/air mixtures resulting from leaks

• Asphyxiating atmosphere resulting from leaks of non-flammable gases

• Leaks caused by components shrinking at very low temperatures

• “Oxygen rich” liquid air condensing on outside of transfer hoses or piping caused by very low temperatures

• Damage to carbon steel and elastomeric components resulting from exposure to cryogenic temperatures

• Unexpected functioning of safety valves or bursting discs on containers


Flammable

• Not just flammability• Think RICH – asphyxiation


Hydrocarbon Gases• Contain hydrogen and

carbon in their make-up– Flammable– Non-corrosive– Non-toxic– Colorless

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Common Hydrocarbons• Methane• Ethane• Ethylene• Acetylene• Propane• Propene• Methyl acetylene• Butane• Butene

• Isobutane• Isobutylene• Butadiene• Cyclopropane• Cyclobutane• 2,2 Dimethyl propane


Explosion PropertiesSubstance LEL UELMethane 5 15Propane 2 9.5Ethylene 2.7 34Acetylene 3 100Hydrogen 5 75


Liquefied Petroleum Gas• LP Gas or LPG –

– Any material with a vapor pressure not exceeding that allowed for commercial propane

– Composed predominantly of the following hydrocarbons, either by themselves or as mixtures: propane, propylene, butane (normal butane or isobutene) and butylenes


Liquefied Natural Gas• Also called LNG • A fluid in the

cryogenic liquid state that is composed predominantly of methane


Compressed Natural Gas• Also called CNG • A gas in the vapor

state that is composed predominantly of methane


Oxygen• Not flammable• Sensitizes flammable and

combustible materials requiring less input heat for ignition

• In some cases, materials impregnated with oxygen can be ignited with static electricity

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LOX + Asphalt



Monitoring andDetection

No Nasal Chromatography


Basic Monitoring


Broom Detection• Broom used to

detect burning hydrogen, which burns light blue to almost invisible


Detection• Similar “broom” method may also be used:

– If attempting to detect presence of chlorine• Wrap clean cloth around broom.• Put ammonia on cloth and wave in suspected chlorine

cloud.• If cloth fumes, you have detected presence of chlorine

– If looking for ammonia leaks • Wrap cloth treated with chlorine bleach around broom• Wave in suspect area• If fuming occurs, ammonia is present


Non-Instrumental Methods

• Soap solution applied to potential leak points– Quick & easy– Alcohol based used for freezing

temperatures– Small leaks of water soluble gases may

not be detected– Can interfere with other methods

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• Aqueous solutions held by leak points or chemical sprays– Ammonia for acid gases– Hydrochloric acid for ammonia or

amines



• Wet pH or litmus paper for acid or base gases

• Potassium iodide (KI) test strips-fluorine, F2 mixes


Leak Detection Limits (cc/sec)

• Soap solution– 1 x 10-3 to 1 x 10-5*

• Test papers– 1 x 10-3 to 1 x 10-5*

• Chemical sprays– 1 x 10-3

• Instrumentation– 1 X 10-5 TO 1 X 10-9*

* Indicates special procedures


Leak Detection Requirements• Portable• Extractive• Fast response• Ergonomically suited for use in PPE• Minimum of interferences• User must know:

– Operation & Limitations– Interferences– Potential Leak Points– False Responses


Electronic Leak Detection• Can be extremely sensitive

– Detects leaks that are quality issues for micro contamination

• May be expensive and sophisticated• Must be maintained and calibrated• Must be used properly• Operator must be knowledgeable

– Instrument is functioning properly– Good procedures– Know limitations and interferences

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Electronic Leak Detection• Methods of Detection

– Thermal conductivity– Electrochemical– Paper tape– Solid state sensor – Infrared spectrometry– Mass spectrometry– Gas chromatography– Flame emission spectrometry

• Sampling methods– Diffusion– Extractive


Monitoring• To determine leaks,

use various detectors:– Combustible gas

indicators (CGI)• You will need to

know:– Gas LEL/UEL and

IDLH limits before monitoring for gas

• Gas detector (gas specific)


Hydrogen has a60% responseFactor for CO


Radioactivity


Thermal Conductivity Detectors

• The refrigerant gas leak detector– Thermal conductivity detectors measure

the change in thermal conductivity of the air drawn across a resistance cell.

– The larger the difference in thermal conductivity of the gas and air, the greater the sensitivity and the more easily it can be found.


Portable Leak Detector

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Detectors



Cylinders


Have You Heard the One• Employee killed when cylinder

turned into a rocket because its valve was knocked off

• Employee suffocated after entering a space filled with nitrogen

• Facility damaged when acetylene cylinder heated up and exploded

• Eyebrows singed when lighting a gas BBQ



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Compressed Gas Hazards• Principal hazards:

– Extremely High Pressure– Toxicity – Reactivity– Instability– Flammability– Extreme Low Temperature– Asphyxiation– Radioactivity


Compressed Gas Hazards• When things go wrong:

– Have Flown Over a Half Mile– Penetrated Brick Walls – Can Displace Oxygen in Extremely Large Areas– Can Oxygen-Enrich Extremely Large Areas– Can Spin and Ricochet Completely Out of

Control– Can Immediately Freeze Exposed Skin– Can Explode With Tremendous Force– Can be Virtually Unstoppable

Continued



Construction


..

..VeryVeryCold

Liquid

High Pressure

Low Pressure

ArO2H2N2

CO2Cl2NO2

PorousMass

AcetoneSolvent

42%Volume

FusablePlug

Acetylene

Cryogenic

P>900psig P

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Cylinder Design

• Specification, design, use, handling, and transportation of non-flammable, flammable, and poison gas cylinders are regulated by DOT, CGA, and OSHA.


• Valves and safety relief devices must be protected against damage– Use of caps– Boxing– Recessing


Protective Caps


Cylinders• Construction must be

compatible with the material contained– Low carbon steel– High carbon steel– Manganese steel -1946– Molybdenum steel– Chrome molybdenum

steel– Aluminum– Composite


Size / Capacity


Half Ton Container

Valve will dispense gas

Relief valve

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Cylinders• Must be marked legibly:

– Cylinder specification– Service pressure– Manufacturer– Original hydrostatic date– Retest dates

• Labels showing material contained


Markings•Labeling required to identify the gas in storage and during shipment

•Nomenclature related to the cylinder and its contents will assist in the safety process• Low pressure: Below 900 psi• High pressure: 900 psi or greater


Marking


Tare WeightDiameterWater capacity

Cylinder spec

PressureSerial

ManufacturerCode

Test date


Color Codes• No US requirement – each

manufacturer• Cylinder shells can also be color

coded to better identify the contents permitted into the specific type of cylinder– This eliminates cross-contamination by

introducing non-compatible gases into non-specification cylinders


Medical Gas Color Codes• Medical gases will

often be a blend of a parent gas with fractions of other gases introduced for purity and stability

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Labels

• Labels are those approved and specified by DOT.

• Must remain on cylinder until cleaned or filled with a different material calling for a different label.


Labels



Safety Devices:• Check valve: prevents

reverse gas flow• Flash Arrestor: prevents

ignition source from reaching regulator and cylinder for flammables

• Excess Flow Valve: restricts flow in the event of a gas line break


Safety Relief Devices

• Types -– Spring loaded relief valve– Rupture disk– Fusible plug

• Not permitted in poison service• Not required in other services

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Pressure Relief Valve (PRV)• May be activated by

pressure, temperature or spring to permit container contents to escape, thereby averting a container rupture

• The PRV is in the product line


Fusible Plug/Combination• Fusible plug melts at a

designated temperature and permits the product of a cylinder to be released to avert a catastrophic rupture

• Combination relief: One with a rupture disk and fusible plug

• Both are non-resealing


Rupture Disk• Rupture disk (frangible

disk) - Operating part of a PRV: ruptures at a predetermined pressure allowing cylinder contents to escape

• Non-resealing• Poison gas cylinders do

not have a PRV depending on their classification (PRVs are prohibited)


Moving Cylinders• Do not lift cylinders by

the cap.• Never drop cylinders

nor permit them to strike against each other or against other surfaces violently.


Storage

• Local Regulations• Storage rooms• Highly flammable substances• Protection of cylinders• Care of cylinders

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Should NOT be This


Storage• Proper ventilation• Out of the weather• Not subject to

temperature extremes• Segregate gas types to

eliminate fire or chemical reaction hazards

• Use good house keeping practices

• Post signage


Storage


Proper nesting supports allcylinders bycontact at three points

At gas manufacturers and distributors not user work sites, proper nesting is considered safe storage by the compressed gas industry.


Transportation


Multi Unit Tank Car Tanks

• Classification - multi unit tank car tanks are classified as DOT 106A or DOT 110A

• Capacity - at least 1500 pounds and not more than 2600 pounds water capacity

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Transportation


Valve Protection


Valve Arrangements

Gas

Liquid


DOT 106A


DOT 106A - Head

Gas

Liquid


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“Y” cylinder - overview

DOT 3AA 2400(non-bulk container)


TW – 563 Kgs, Product Wt. – 553 Kgs



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Cylinder Hazards• Material Hazards

– Flammability– Spontaneously

flammable (arsine, silaneand phosphine)

– Corrosivity– Reactivity– Poison– Carcinogenic

• Container Behavior– Frostbite– Rupture– Rocketing– Boiling liquid

expanding vapor explosion (BLEVE)



When Things Go Wrong

• Regulator failure• Failure of pipework or

tubing connecting cylinder to other equipment

• Over pressurisation• Damage caused by

impact e.g. falling cylinder or vessel

• Damage caused by fire


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terms critical temperature 2 materials - short.pdf · 2019. 11. 3. · lp gas or lng – the...

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