Corporate Health and Safety ArcelorMittal

Corporate Health and Safety ArcelorMittal

March 4th , 2011

Confined Spaces

training

confidentialMarch 4th, 2011 2

Summary 1) Introduction 2) Definitions 3) Responsibilities

3.1) Permit Issuer 3.2) Permit Receiver 3.3) Responsible Officer3.4) Managers and Supervisors3.5) Safety Departments3.6) Contractors3.7) Authorised Entrant3.8) Standby Person

4) Confined Space Entry Process 4.1) Additional for Man – Baskets

5) Confined Space Procedures 6) Atmosphere Conditions in and around

Confined Spaces 6.1) Oxygen DEFICIENT Atmospheres

6.2) Oxygen ENRICHED Atmospheres 6.3) Flammable Atmospheres 6.3.1) Definitions

6.4) Toxic Atmospheres 6.5) Mostly common Gases in

Confined Spaces6.6) Lower Explosive Limit vs. Upper

Explosive Limit 7) Atmosphere testing before entering

7.1) Testing instruments 8) Preparing for Entering a Confined

Space 8.1) Ventilation 8.1.1 Ventilation forms

8.2) Isolation of Space 8.3) Standby Person8.4) Rescue and Emergency

8.4.1) What are some emergency response precautions?

9) Personal Protection Equipments (PPE) 9.1) Maintenance of PPE

10) Is worker training important? 11) Potential Hazards Overview


Working in confined spaces presents a variety of hazards and increased risk of injury to those in the immediate area.

The Occupational ArcelorMittal Health & Safety Regulation, establishes specific requirements for safe entry into confined spaces.

This guideline details controls to be adopted for entry to or work in or around a confined space.

This document is based on specific legislative requirements as contained ArcelorMittal Standard for Confined Spaces

1. Introduction


1.1 REX

• Lazaro Cardenas Jan 2010 Fatality Victim went to take an oil sample in the oil deposit of the hydraulic system of the Bischoff in Blast Furnace area. Apparently the cause of death was due to a non noticed gas presence (CO) in the area of the seal of the piston No.1. The victim decided not to use a breathing mask with air line and went alone without gases detector.

Build up of asphyxiate or toxic gas

Sept 08 and Jan 10

CO – Gas Fatality

• Saldhana Sept 2008 Fatality As the flange was lifted from its position using a crane, a large

quantity of CO rich gas escaped as a result of an unexpected opening of one of the isolating valves. This caused a sudden build-up of CO-gas in the immediate environment. The deceased and his colleagues at that point in time were positioned on the 5 meter level, next to the flange. Due to the amount of gas escaping in the vicinity of the 3 employees, the CO monitors used went into the alarm mode. The deceased together with his colleagues attempted to evacuate, but due to the intake of CO gas at the compressor, they inhaled CO via their independent air-line supply.


Nitrogen• Vanderbijlpark April 2008 First aid

A colleague noticed that the victim was losing consciousness after he had instructed him to insert the last bolt of the keeper plate for the limiting stopper. He himself also started to feel dizzy. Another colleague saw what was happening and grabbed the victim on his arm and removed him from the area. He immediately suspected that there was gas in the area even though their gas monitors had not given an alarm. He suspected that it could be nitrogen exposure. He had the nitrogen supply to the gearbox checked : it was noticed the nitrogen valve was still open.

Build up of asphyxiate or toxic gas

April 08 and June 09

Nitrogen – Gas First Aid / Methane – Gas Fatality

1.1 REX

Methane • Tenteskaya June 2009 Fatality

The concentration of methane in the face was 0.4-0.5% and 0.45% in the return air; the conditions of the face was satisfactory. The concentration of methane in return air increased up to 0.7%. The operator of air and gas control informed the shift manager of this increase. Then there was a sharp increase of methane concentration. The stand-by auxiliary fan switched on automatically and its shutoff took place straight away.


• Vinton October 2010 Fatality On Monday October 18, 2010 at about 2:30 a.m. the victim, an equipment operator with 4 years of seniority in this department, was helping the crew in startup preparations (it is routine to stop production at 11 pm Friday and start up Sunday night shift for the coming week operations, on 5 day working schedule). It is believed that he started lighting up of the tempering furnace.At this time, the assumption is that the victim had started the lighting process and during this process, the explosion occurred.Before this incident, gas was not detected (by smell) by the crew nor the supervisor of the shift. Immediately following the sound of the explosion, the work crew (operators and supervisor) initiated the emergency procedure, which included workforce count. The victim was found on the floor unconscious, adjacent to the furnace, with refractory material and furnace roof metal plates around him, suffering from a severe head-face trauma.

Explosive mixtures or zones of explosive atmospheres

October 10

Fatality

1.1 REX


•Termitau December 2010 Fatality A team consisting of 3 men was removing a hanging charge (cleaning of bunker). The victim was in a danger zone of possible charge coal collapse at the bottom of the bunker at the height of 3m and was staying on a metal ladder installed in the bunker (height of ladder – 12 m), he wore a harness and the too long lanyard he used was attached (fastened) to the harness. Two supervisors were on the upper platform of the bunker, they should ensure the safety of the victim. They fastened the lanyard to the top step of ladder .Since the safety lanyard attached to the harness of the victim was too long, when charge coke collapse happened (charge fell down from the bunker walls), the coke hit the victim who fell down on the bottom of the bunker and was covered with batch mixture (sanded-in), as a result he suffered fatal injury (asphyxia of respiratory tract).

Engulfment in confined space by collapsing material

December 10

Fatality

1.1 REX


• Newcastle December 2009 Multiple FatalitiesThree persons entered the vessel via the cat ladder with gas monitors on their person. On reaching a particular level the persons collapsed onto the platform. The gas monitors were seen to give an alarm by the operator on top of the furnace, and the persons collapsed almost simultaneously. Owing to the fact that one person’s leg was caught in the cat ladder, the platform could not be raised to evacuate the persons. A further two persons entered the vessel via the cat ladder in an attempt to rescue the persons on the platform; they too collapsed and fell beneath the platform. The cause was an oxygen deficiency due to apparent ingress of argon through the bottom stirring system due to an inadequate isolation of bottom stirring gas

Atmospheres not having safe level of oxygen, in particular due to presence of CO, CO2, Ar, N2

December 09

Fatality

1.1 REX


• Gent February 2011 FatalityIn the evening the flexible hoses of the bottom stirring were reconnected, but the Nitrogen and Argon circuits were still under isolation, both protected with a block and bleed system. The operator took property of the isolation to guarantee that Nitrogen and Argon remained locked out. Later he started the work in the BOF together with his colleague to remove the scaffold. The work has been started without wearing a multi-gas meter as up till now in the investigation, they were not found yet. When trying to remove the first part of the work platform, The operator fell unconscious, while his colleague was out of the BOF. The first idea was not linked to gas risk and his colleague called in an AMG maintenance worker for help. With the elevator cage, he went down ( +/- 12 m) in the BOF, felt immediately the lack of oxygen and fell also unconscious. Local AMG workers linked now the accident with gas, and threw a compressed air hose in the BOF. The emergency services which had been called, came to the spot and evacuated both victims out of the BOF. They were able to reanimate the second victim. The reanimation attempts on the first worker however failed

Atmospheres not having safe level of oxygen, in particular due to presence of CO, CO2, Ar, N2

February 11

Fatality

1.1 REX


Confined space is any enclosed or partially enclosed space or spaces where movement is limited or physically restricted and that :

1. has limited or restricted means of entry or exit (sometimes needing a mechanical system) and

2. is large enough for a person to enter to perform tasks and3. is not designed or configured for continuous occupancy or work and4. may have at any time an atmosphere with potentially harmful

contaminants, an unsafe level of oxygen, stored substances that may cause engulfment or where there is a risk of death or serious injury from hazardous substances or dangerous conditions and

5. present special hazards to workers, including risks of toxic or asphyxiant gas accumulation, fires, falls, flooding, and entrapment may be classified as permit-required confined spaces depending on the nature and severity of the hazard.

2. Definitions

It is not possible to provide a comprehensive exhaustive list of confined spaces. Some places may become confined spaces when work is carried out, or during their construction, fabrication or subsequent modification.


• Confined spaces can be below or above ground. • Confined spaces can be found in almost any workplace. • A confined space, despite its name, is not necessarily small.

• Confined spaces include, but are not limited to:– Storage tanks, silos or areas of storage, vats, hoppers, utility vaults, tanks, sewers,

pipes, access shafts, truck or rail tank cars, aircraft wings, process vessels, boilers, pressure vessels, tank-like compartments that have only a manhole for entry, ceiling and floor spaces, spaces occupied by pipes and cables (considering galleries in particular). Ditches and trenches may also be a confined space when access or egress is limited

– Open-topped spaces such as pits, or grease traps, or excavations more than 1.5 meters deep.

– Pipes, pumps, sewers, shafts, ducts, drains, tunnels, cellars, spaces under equipments/installations, basements and similar structures.

– BOF (Basic Oxygen Furnace) vessel, EAF (Electric Arc Furnace) vessel etc … since entry / exit is not easy and / or gas may be present


• .


Categorizing Work Space

• Space large enough to enter and• Limited or Restricted entry or exit and• Not designed for continuous worker occupancy.

NO Not a confined Space

Permit Required Confined

Space

NonPermit

Required Confined

Space

Confined Space

Hazardous Atmosphere

Engulfment Hazard

Configuration Hazard

Any other recognizedserious hazard

YES

YES NO

Or

Or

Or

In addition, it contains one or more of the following


Permit-required confined space• "Permit-required confined space (permit space)" means a confined space where one or

more of following hazards are present;

– The potential to contain a hazardous atmosphere (AM ST 012)– Not have a safe level of oxygen ( e.g. following a nitrogen purge) – The potential for engulfing the entrant– A configuration that might cause an entrant to be trapped or asphyxiated by

inwardly converging walls or by a floor that slopes downward and tappers to a smaller cross section

– Contains any other recognized serious safety or health hazards that can’t be eliminated and the confined space can’t be maintained in a condition safe to enter.

In those cases the entry points must clearly indicate that a permit is required prior to entry.

Non Permit-required confined space• “Non-permit confined space” means a confined space that doesn’t contain or, with

respect to atmospheric hazards, doesn’t have the potential to contain any hazard capable of causing death or serious physical harm


3.1 Permit Issuer

• Ensure that hazards associated with the confined space have been: – Identified– Assessed– Appropriate controls adopted.

• Inform Permit Receiver:– The locations of the spaces and the potential hazards associated with the

respective spaces– The requirement that only authorised, trained personnel may enter the spaces

using the procedures outlined in these guidelines.

• Ensure completion of entry permit is issued.

• Ensure that all personnel involved in the work are properly trained to perform the required tasks.

3. Responsibilities


3.2 Permit Receiver

• Adhere to the Entry Permit requirements.• Ensure the job is performed in a safe manner.• Inform Entrants and Standby Persons of the locations of the spaces, the potential

hazards associated with the respective spaces, and the requirement that only authorised, trained personnel may enter the spaces using the procedures outlined in these guidelines.

• Be aware of the hazards that could exist and have the necessary controls in place.• Satisfy themselves that they understand the requirements of the permit.• Be skilled, qualified trained and competent to perform this work.• Ensure that appropriate control measures are followed (e.g.: placement of locks and

tags according to lock-out/tag-out procedures, ventilation if necessary).• Communicate entry permit requirements to any authorised entrant working in the

space. • Make equipment and area safe performing above tasks.


3.3 Responsible officer

• Ensure that contractors engaged by ArcelorMittal are aware of any occupational health and safety hazards that may exist in the area in which they are working.

• Ensure that contractors work safely and complete the work as specified in permits and other associated documents.

• Ensure that prior entering a confined or a permit space, a risk assessment has been conducted.

• Ensure that before an employee enters a permit space, the internal atmosphere has been tested with a calibrated direct-reading instrument in the following order:

– Oxygen content (oxygen-deficient or oxygen-enriched atmospheres)– Flammable gases and vapors– Potential toxic air contaminants


3.4 Managers and Supervisors

• Supervisors must understand the work for which a permit has been sought and understand isolation and Lockout / Tagout ArcelorMittal procedures,

• Ensure adequate protection is provided to the entrants by verifying adequate Lockout / Tagout and that all hazards are securely isolated.

• Ensure that all personnel involved are aware of the hazards associated with the space.

• Ensure that a permit is granted before work starts.

• Ensure that the person(s) doing the work are appropriately qualified to do the work.

• Ensure that all checks are undertaken to ensure that the permit was used correctly.

• Ensure that rescue services informed and available as possible prior to entering.

• Ensure appropriate persons are informed when a job is completed or suspended and that the permit is cancelled.


3.5 Safety Departments

• Provide technical guidance on the application of these guidelines.• Evaluate and update the permit to work guidelines at the review period or as

procedures change.• Provide safety expertise and regulatory guidance to Permit Issuer.

3.6 Contractor

• Comply with the requirements as detailed in these guidelines.• Ensure entry to a confined space is carried out under a work permit and in accordance

with ArcelorMittal Safety Standard Confined Space.• Provide evidence of confined space training to permit issuer, authorised entrants,

standby persons and supervisors.• Shall not enter a confined space without a granted ArcelorMittal confined space

permit.• Prepare safe work procedures and/or risk assessments for confined space work prior

to entering.


3.7 Authorised Entrant

• Assessed as competent to enter a confined space• Understand the potential entry hazards and be aware of signs and symptoms of

hazardous environment exposure.• Ensure that appropriate control measures are followed (e.g.: placement of locks and

tags according to lock-out/tag-out procedures, ventilation if necessary).• Ensure that there exist defined criteria to determinate if periodic re-testing is

necessary depending on operations and conditions in and around the permit space.• Maintain communication with the Standby Person at all times.• Evacuate the space immediately upon an emergency, a gas detector alarm occurs or

notification by the Standby Person.• Alert the Standby Person and exit the space immediately whenever:

– a warning sign or symptom of exposure to a dangerous situation is recognized– a prohibited condition is identified– an evacuation alarm is activated.

• Follow the requirements as stipulated on the confined space entry permit


3.8 Standby Person

• Remain outside the Confined Space at all times or until relieved by another Standby Person. Activities that may interfere with these duties are prohibited.

• Observe the work conditions in the confined space• Monitor entrants during the job and during entry & exit to help insure their safety.

– The attendant may not abandon his post for any reason while personnel is in the space unless relieved by another qualified attendant.

• Control if entrants properly use/worn their PPE

• Monitor continuously atmospheric conditions in the space prior to and during work (if needed).

• Control if the ventilation system is running well (if needed)

• Control access to the confined space.

• Assess hazards in and around the space, and take measures if needed.

• Keep records related to the confined space work, such as air test results, personnel entry/exit, etc…

• Maintain continuous communication with the Authorised Entrants so as to be aware of any problems, which may occur.

• Initiate emergency procedures, including rescue procedures, if necessary.• Stop the job & evacuate the people if any non conformity (internal or external) is detected


Prior to entry of a confined space Own personnel or Contractor personnel are required to:

1. Realise a new/own HIRA and compare it with the existent one.2. Complete a confined space entry permit (in accordance with ArcelorMittal

Standard if needed) 3. Obtain a ArcelorMittal permit for confined space entry (if needed)4. Verify that all personnel involved in confined space entry are aware and

understand their responsibilities5. Verify that personnel are trained in accordance with requirements of confined

spaces 6. Provide the necessary safety equipment, supplies and monitoring equipment to

their personnel. Key items include atmospheric monitoring devices, barricades to isolate work area, communication devices for the entrant and stand-by persons and adequate lighting.

7. Wear all PPE’s, safety harnesses‘ and other devices requested by the approved risk assessment.

4. Confined Space Entry Process


4.1 Permit system– The permitting process must include the following elements:

• A Risk Analysis, including the need for a competent person to assess such risks as oxygen or contaminants levels, temperature extremes, and concentrations of flammable substances

• Isolation procedures for contaminants and other energy sources• Need for ventilation, the requirement for breathing apparatus• The sign-in and sign-out of all persons entering the confined space; internal lighting

and signalling• Emergency lights, auxiliary lights• Atmospheric protection conditions;• Display of the permit• Communication equipment• Safety specification of equipment to be taken into the confined space• Barricading (isolated the work area)• Rescue plan and equipment• Standby person• All the work procedures.• Modification possibilities:

– If a new hazard is recognized or introduced during the course of work, then the permit must be modified and revalidated

The Risk Analysis may require that people working in confined spaces wear a safety harness, connected with a cable or cord extending outside the confined space, allowing easy evacuation in case of emergency


The internal site procedure must refer to the Law and the ArcelorMittal Standard ST 002 and ST 012

– An identification register of all existing Confined Spaces and Restricted Areas on site– A risk assessment must be performed prior to any work occurring in the confined space.– Different confined space entry permits are required for entry into a space, depending on the

type of work being conducted such as cold or hot work.– Isolation of all potentially Hazardous Services prior to entry into the confined space

hazardous services that are normally connected to the confined space must be isolated or otherwise controlled.

– Air monitoring must be performed prior to entry into the confined space. If work stops for a period of more than 1 hour and the confined space has not been occupied for this period a new gas test will be required.

– Prior to entry, the confined space must be cleared of all contaminants (purging)– An emergency plan should be documented and communicated to all persons working in or

around the confined space– Any person required to issue/receive permits or work in or around a confined space must be

appropriately trained and assessed as competent prior to undertaking these activities.

5. Confined Space Procedures


6. Atmosphere Conditions in and around Confined Spaces

The below pictures shows different ranges of Oxygen in the Air.

To work in safe conditions in the confined space the oxygen level must be between (19,5 – 22,5) %

Oxygen deficient atmosphere starts from < 19,5 %Oxygen enriched atmosphere starts from > 22,5 %

In both cases entry into confined spaces is prohibited

Difficult breathing, death in

minutes 6 %

Faulty judgement,

rapid, fatigue 14 %

Impaired judgement

and breathing 16 %

Maximum for Safe Entry 22.5

%

Minimum for

Safe Entry 19.5 %

Oxygen enriched,

extreme fire hazard

> 22.5 %


Oxygen Deficiency Can Be Caused by CONSUMPTION

• “Hot work” (welding)• Breathing• Chemical reactions (ex. Oxidation of chemicals or metal)• Biological action (ex. Decomposing organic matter)

19.5 % Minimum acceptable oxygen level. 15 - 19% Decreased ability to work strenuously.

Impair coordination. Early symptoms. 12 - 14% Respiration increases. Poor judgment. 10 - 12% Respiration increases. Lips blue. 8 - 10% Mental failure. Fainting. Nausea

Unconsciousness. Vomiting. 6 - 8% 8 minutes fatal,

6 minutes 50% fatal4 - 5 minutes possible recovery.

4 - 6% Coma in 40 seconds Death

6.1 Oxygen DEFICIENT Atmospheres


Oxygen Deficiency Can Be Caused by DISPLACEMENT

Not having a safe level of oxygen, in particular due to presence of:

• Argon (Ar)• Nitrogen (N2) (e.g. following nitrogen purge). • Helium (He)• Carbon monoxide (Co)• Carbon Dioxide (Co2)• Bacterial actions (fermentation process)• Formation of rust on the surface of the confined space (iron oxide/ corrosion)• Consumption of air by the amount of people working in a confined space • Cleaning agents, adhesives, or • Other chemicals

6.1 Oxygen DEFICIENT Atmospheres


• Oxygen level above 22.5%.

• Causes flammable and combustible materials to burn violently when ignited.

– Hair, clothing, materials, etc.– Oil soaked clothing and materials.

• Never use pure oxygen to ventilate.

• Never store or place compressed tanks in a confined space.

6.2 Oxygen ENRICHED Atmospheres

Leak of oxygen

CellarLiege Feb 2008 Fatality

• The two victims went out to the cellar to carry out a simple work. Suddenly, the atmosphere was kindled and the fire took the two people. One died directly, the other died at hospital. The origin of the accident was a very high concentration of oxygen due to a leak in an oxygen pipe that was buried outside the building.


• 2 Critical Factors:– Oxygen content in the air.– Presence of a flammable gas, or vapor– Presence of dust (visibility of 5 inches/ 12 cm

or less)

• Proper air/gas mixture can lead to explosion

• Typical ignition Sources:– Sparking or electric tool.– Welding / cutting operations.– Smoking

6.3 Flammable Atmospheres


• The threshold limit value (TLV) of a chemical substance is a level to which it is believed a worker can be exposed day after day for a working lifetime without adverse health effects.

• The TLV for chemical substances is defined as a concentration in air, typically for inhalation or skin exposure. Its units are in parts per million (ppm) for gases and in milligrams per cubic meter (mg/m³) for particulates such as dust, smoke and mist.

• Threshold limit value – Short-term exposure limit (TLV-STEL) : spot exposure for a given substance in the air of the workplace, to which the worker may be exposed for a short time (duration of 15 minutes, that cannot be repeated more than 4 times per day)

• Threshold limit value –Time weight average (TLV-TWA) : indicates the average concentration in air of workstations in a given pollutant that, given the current state of knowledge, does not endanger the health of the vast majority of healthy workers exposed to them, and this for a duration of 42 hours per week, a rate of 8 hours per day, for long periods. The pollutant in question may be in the form of gas, vapor or dust

• The TLV-TWA must always be respected

6.3.1 Definitions TLV-STEL and TVL-TWA


6.4 Toxic Atmospheres

• Stored Products Source:– Gases released when cleaning. (e.g.: purging by Argon (Ar))– Materials absorbed into walls of confined space.– Decomposition of materials in the confined space.

• Source by work performed:– Welding, cutting, brazing, soldering.– Painting, stripping, scraping, sanding, degreasing.– Sealing, bonding, melting.

• Areas adjacent to a confined space: venting or entering into space

(TLV-TWA) Limit 8 Hour work shift

(TLV-STEL) Limit 15 min work working

[ppm] [ppm]Hydrogen Sulphide (H2S) 5 20Carbon Dioxide (CO2) 5 30Carbon Monoxide (CO) 35 50Nitrogen Dioxide (NO2) 1 3Nitrogen Monoxide (NO) 25 50Sulphur Dioxide (SO2) 2 5

Gas


PPM Effect Time

35 Permissible Exposure Level 8 hours 200 Slight headache, discomfort 2 - 3 hours 400 Headache and nausea 1 - 2 hours 800 Headache, dizziness, nausea 45 min.1 600 Headache, dizziness, nausea 20 min.3 200 Headache and dizziness 5 - 10 min.6 400 Headache and dizziness 1 - 2 min.

• Colorless chemical asphxiant / odorless gas / flammable gas / Deadly! • Quickly collapse at high concentrations • Slightly lighter than air• Primary source:

– incomplete combustion of organic material– Gasoline-fueled combustion engines– ….

• Signs/Symptoms: – Confusion. Dizziness. Headache. Nausea. – Unconsciousness. Weakness.

6.5.1 Carbon Monoxide (CO)

6.5 Mostly common Gases in Confined Spaces and Gas Hazard Atmospheres

Possible human effects if you are trapped in Carbon Monoxide atmosphere with this different high exposure levels

(TLV-TWA) Limit 8 Hour work shift

[ppm]Australia 30China 20Japan 50Czech Republic 30Hungary 33Kazakhstan 20Poland 23Romania 20Begium 25France 50Germany 30Netherlands 29Spain 25UK 35Brasil 39Mexico 50South Africa 55USA 25/35Canada 25

Carbon Monoxide (CO)


PPM Effect Time

10 Permissible Exposure Level 8 hours50 - 100 Mild Irritation - eyes, throat 1 hour100 Desensitizes olfactory nerve 2 - 5 min.250 - 350 Unconsciousness, death 4 - 8 hrs.500 -600 Unconsciousness, death 30 - 60 min.>1000 Unconsciousness, death minutes

• Colorless / Very strong asphyxiant with rotten egg odor / flammable gas / Deadly! • Odor threshold: 0.02-0.2 ppm• Heavier than air • possibly no warning at high concentrations

• Primary source: – incomplete combustion by-product of the decomposition of organic matter / 4 times– …

• Signs/Symptoms: – Strong odor BUT Fatigues your senses . – Very high concentrations lead to cardio respiratory arrest because of brainstem toxicity. – Affect nervous system

6.5.2 Hydrogen Sulfide (H2S)

Possible human effects if you are trapped in Hydrogen Sulfide atmosphere with this different high exposure levels


6.5.3 Methane (CH4)

• Colorless/odorless flammable gas, or scented

• Natural gas, swamp gas.• Primary source:

– Due to gas leak or organic decay

• LEL = 5%; UEL = 15%


6.5.4 Argon (Ar)

• Colorless / odorless, non-flammable gas and tasteless mixture, it is the most abundant of the noble gases on Earth and the one most used in industry

• Heavier than air.

• Primary source: – Purging of confined spaces– Firefighting in electrical or computer rooms– BOF (Basic Oxygen Furnace) vessel,– EAF (Electric Arc Furnace) vessel

• The main health hazard associated with releases of this gas mixture is asphyxiation by displacement of oxygen


6.6 Lower Explosive Limit vs. Upper Explosive LimitDefinitions:

Lowest concentration (percentage) of a gas or vapour in air capable of producing a flash of fire in presence of an ignition source ( arc, flame, heat).

Concentrations lower than Lower Explosive Limit (LEL) [ Lower Flammable Limit (LFL)] are 'too lean' to burn.

Concentrations lower than Upper Explosive Limit (UEL) [ Upper Flammable Limit (UFL)] are 'too rich' to burn.

UEL

LEL

Too lean

FlammableRegion

Flash Point

Temperature

Con

cent

ratio

n in

Air

Too rich

10% LEL

Important to point out where 10% LEL is in relation to LEL.


Why is 10% used?

• The combustible gas detection instrument measures % LEL, not Actual % gas in air. Depending on calibration gas used, some gases will give a much lower LEL reading than the actual LEL concentration.

• Their is a very small percentage difference at 10%. For this reason, 10% LEL should be used as the max LEL concentration for worker entry.

Air100%

Methane100%

Air0%

Methane0%

Too Rich

5.3%LFL

15.0%UFL

Boom!

Too Lean

Methane example

It’s always a good idea to keep the fire and/or explosion

triangle in mind.


• Before a person enters a confined space, it shall be ensured;

– the concentration of flammable contaminant in the atmosphere is below 5 % of its LEL– Entry shall not occur to a confined space when flammable contaminants are greater than or

equal to 5% LEL – Where a concentration of flammable contaminant is found to be more than 5% and less than

10% of its LEL, all persons must leave the confined space unless a continuous monitoring, suitably calibrated flammable contaminant detector is used in the confined space at all times while persons are present in it.

– Where a concentration of flammable contaminant in the atmosphere of a confined space is found to be 10% of its LEL or more, all persons must leave the confined space.

"Lower Explosive or Flammable

Limit" (LEL/LFL)

"Upper Explosive or Flammable

Limit" (UEL/UFL)(%) (%)

Hydrogen - H 4 75Methane - CH4 5 15

Ammonia - NH3 15 28

Acetylene (ethyne) - C2H2 2.5 81

Carbon monoxide - CO 12 75

Ethylene (Ethene) - C2H4 2.75 28.6

Ethane - C2H6 3 12.4

Cyclopropane 2.4 10.4Propane - C3H8 2.1 10.1

Benzene - C6H6 1.35 6.65

Gas

6.6 Lower Explosive Limit vs. Upper Explosive Limit


7. Atmosphere testing before entering

• Air monitoring is required to be performed prior to entry into the confined space to ensure that the atmosphere is safe prior to entry.

• If work stops for a period of more than 1 hour and the confined space has not been occupied for this period a new gas test will be required.

• After ventilation period (if ventilation is necessary);

• Initial testing should be carried out by a “Competent person” who will issue a certificate stating whether the space is ‘safe for man’ and/or work, and if any special conditions are to be observed.

• In no case should the operator / worker is considered to be a “Competent Person” – even if he is equipped with his own personal testing equipment.

• Ventilation should be stopped about 10 minutes before tests are made and not restarted until the tests are completed.


7. Atmosphere testing before entering

• The testing should be carried out in the following sequence

– Oxygen-deficient or -enriched atmospheres– Flammable atmospheres– Toxic atmospheres when considered necessary

• To evaluate the measurements taken, the following limit values should be used.

• Continuously monitoring is required for the whole work period


Always test the air at VARIOUS levels to be sure that the entire workspace is safe

• Good Air Good Air

• Poor Air Poor Air

• Deadly Air Deadly Air

Top of vessel

Bottom of vessel

Middle of vessel

Good air near the opening does

NOT mean there is good air at the

bottom !

This constellation is NOT all the time given (see example next page)


• See some examples of Specific Gravity ( kg/m3) of Gases.

Specific Gravity1)

- SG - ( kg/m3)Hydrogen 0.0696

Helium - He 0.138

Coke Oven Gas 0.44

Methane - CH4 0.5537

Ammonia - NH3 0.59

Natural Gas (typical) 0.60 - 0.70

Acetylene (ethyne) - C2H2 0.90

Carbon monoxide - CO 0.9667Nitrogen - N2 (pure) 0.9669

Ethylene (Ethene) - C2H4 0.9683

Nitrogen - N2 (atmospheric) 0.9723

Air 1Blast Furnace gas 1.02

Ethane - C2H6 1.0378

Oxygen - O2 1.1044

Hydrogen sulfide - H2S 1.1763Hydrogen chloride - HCl 1.268

Fluorine 1.31Argon - Ar 1.38

Carbon dioxide - CO2 1.5189

Propane - C3H8 1.5219

Nitrous oxide - N2O 1.530Ozone 1.660

Sulfur Dioxide - SO2 2.264

Benzene - C6H6 2.6961R-11 --> 134a 4.174 --> 5.9

These gases are HEAVIER than Air

Gas

These gases are SAME than Air

These gases are LIGHTER than Air


Warns Against Hazardous Gas Concentrations

• The device reliably warns against hazardous concentrations of the following: carbon monoxide (CO), hydrogen sulphide (H2S), oxygen (O2), carbon dioxide (CO2), sulphur dioxide (SO2), chlorine (Cl2), hydrogen cyanide (HCN), ammonia (NH3), nitrogen dioxide (NO2), nitrogen monoxide (NO), phosphine (PH3) and organic vapours.

Examples of single gas detector(s):

7.1. Testing instruments

The examples shown in the next slides are just 2 of many other existing atmosphere testing devices on the market.

Fill free to make your own choice !



• The device reliably warns against hazardous concentrations of the following: Carbon Monoxide (CO), Oxygen (O2) .




• These Hands Free Single Gas Monitor can detect Carbon Monoxide (CO), Hydrogen Sulphide (H2S), or Oxygen (O2) gases.




• The device reliably warns against hazardous concentrations of the following by changing the sensors:

• Ammonia (NH3), Arsine (ASH3), Carbon Monoxide (CO), Chlorine (Cl2), Hydrogen Cyanide (HCN), Hydrogen Sulphide (H2S), Phosphine (PH3), and Sulphur Dioxide (SO2).

Special Accessories for this detector

• Its unique extender cable allows the sensor to be attached to the end of a 10 foot (+/- 3 m) cable for remote monitoring and quick response.

Examples of multi gas detector:



• The 1 to 4 gas detector reliably detects combustible gases and vapours as well as O2, CO and H2S.

• • The very compact design - no larger than a mobile

phone - and low weight make the device the ideal companion in your daily work.


• An external pump, which can be operated with a hose of a length of up to 20 m, is the perfect solution for remote measurement applications as of tanks, shafts, etc.

• Attention : By using external pumps to extract the gas from tanks it takes a several time to measure the correct gases.

Examples of 4 gas detectors:


Four Gas Confined Space Monitor

• The 1 to 4 gas detector reliably detects simultaneous detection of 4 gases, LEL, O2, H2S & CO

• The very compact design - no larger than a mobile phone - and low weight make the device the ideal companion in your daily work.


• An external pump, which can be operated with a hose of a length of up to 20 m, is the perfect solution for remote measurement applications as of tanks, shafts, etc.

Examples of 4 gas detectors:


Example of controlling a Confined Space (1)

Before entering in Confined Space, it is mandatory, to control this space with a gas detector.

If the cave is too deep, wide,…, a special devices, as an adapted stick, rod, is to use to control the atmosphere .

8. Preparing for Entering a Confined Space


How using the adapted stick:

Use a adapted stick, fixe the 4 gas detector on it, hold it at mini. 20 seconds into the confined space, take it of, read the result and repeat the test in the 4 directions (up, down, left or right and depth)

Example of controlling a Confined Space (2)


8. Preparing for Entering a Confined Space

• Before a person enters a confined space, it shall be ensured;– the atmospheric contaminants in the confined space are reduced to below the

relevant exposure standards

• If concentrations of materials are found to be at harmful levels, the confined space must be ventilated to remove them before entry.

• Ventilation should be continuous where possible because in many confined spaces the hazardous atmosphere will form again when the flow of air is stopped. All openings are to be opened for ventilation including emergency exit.

• De-ballasting a tank does not guarantee a safe atmosphere. Testing of the atmosphere is still required.

• The inert gas fans should not be used to provide fresh air ventilation because contaminants from the inert gas lines could be introduced into the tanks.

8.1 Ventilation


• Use mechanical ventilation– Fans– Air horns

• Make sure air supply is not contaminated– Ventilation air supply must be from fresh air

uncontaminated with flammables, toxins, etc.– Localized exhaust ventilation is better suited to capture

fumes (welding), dust, and chemical contaminants

8.1.1 Ventilation forms

Ventilation must be continuous when there is

an existing or potential atmospheric hazard.


• Blowers & fans provide mechanical dilution ventilation. Be sure the blower is appropriately sized, explosion-proof, and its intake is placed far enough away from any source of

contamination – like an exhaust pipe on a vehicle!

Effective ?

Effective ?

A space under positive pressure will eventually expel the contaminant through an opening, but the time it takes is the real question.

Possible Blowers & Fans problems:


• Respirators must be worn in oxygen deficient atmospheres or when toxins are capable of causing death, incapacitation, impairment of ability to self-rescue, injury, or acute illness due to their health effects.

• A supplied air respirator is required for oxygen deficiency or toxic chemical levels that are Immediately Dangerous to Life or Health (IDLH). An air-purifying respirator (respirators that filter contaminated air) cannot be used in these atmospheres.

• Employees must have complete training on the proper use of respirators.

Possible Respiratory Protection problems


A way to isolate the Space from all Hazards• Close Valves

In order of priority :– Physically remove the connection to the space– Blind flange (assure it can withstand the pressure and is in good state)– Double block & bleed as a last resort if the other two are not possible and only upon

approval of hierarchy

• Cut off any connection which could enable gas penetration. To close valves or other armatures is not safe enough, disconnect the supplies.

• Disconnection is always required, in case an explosive atmosphere could not be excluded.

The supervisor should evaluate the need and the way how for isolation of the confined space from service before entering the space.

8.2 Isolation of Confined Space

wrong right


• Empty the Confined Space– Depressurize, vent & drain,…

• Lockout / Tagout Equipment– Electrical sources– Rotating/reciprocating parts– Hazardous materials– …

• Clean residue from the space ( e.g.: Argon purging)

8.2 Isolation of the possible energies in a Confined Space


• Gaseous fire suppression is a term to describe the use of inert gases and chemical agents to extinguish a fire. Also called Clean Agent Fire Suppression .

• Lockout / Tagout must be realised in case of working in a server or electrical room extinguished by an inert gas ( e.g.: Argon , CO2,..)

– Numerous incidents have occurred where individuals in these Confined Spaces have been killed by carbon dioxide or Argon agent release.

– To prevent such occurrences, additional life safety systems are typically installed with a warning alarm that precedes the agent release. The warning, usually an audible and visible alert, advises the immediate evacuation of the enclosed space.

– Accidents have also occurred during maintenance of these systems, so proper safety precautions must be taken beforehand

Remember, purging a space with an inert gas expels a flammable but leaves no oxygen.

8.2 Isolation of the possible energies in a Confined Space


• A standby person should be assigned to remain on the outside of the confined space and be in constant contact (visual or two-way voice communication e.g. walkie-talkie) with the survey team inside. Routines for communication intervals with the survey team should be established.

• The standby person:– should not have any other duties than to serve as standby and know who should

be notified in case of emergency;– should never leave his post even after help has arrived and is a key

communication link to others onboard;– should be able to communicate sufficiently in a relevant common language.

• Communication between watch personnel (Bridge, Cargo Control Room or Engine Control Room) and standby person should be established

8.3 Standby Person


• Rescuers must be trained in and follow established emergency procedures and use appropriate equipment and techniques (such as lifelines, respiratory protection, standby persons).

• Emergency and evacuation procedures should be agreed and understood by all parties involved in a potential rescue operation.

• Steps for safe rescue should be included in all confined space entry procedures. Rescue should be well planned and evidence should be made available that indicates drills have been frequently conducted on emergency procedures

8.4 Rescue and Emergency

Note:• Unplanned rescue, such as when someone instinctively rushes in to help a

downed co-worker, can easily result in a double fatality or even multiple fatalities if there is more than one would-be rescuer.

• Over 50% of the workers in confined spaces die while attempting to rescue other workers.

• An unplanned rescue could be the last!


• If a situation arises where there is a hazardous condition and the worker does not leave or is unable to leave the confined space, rescue procedures should be begin immediately.

• The Safety Watch is qualified in confined spaces rescue procedures and will be available immediately outside the confined space to provide emergency assistance if needed. The Safety Watch should be familiar with the structural design of the confined space. The Safety Watch is in constant communication with the worker inside the confined space and will:

– Have an alarm for calling for help. – Have all required rescue equipment (for example, safety harnesses,

lifting equipment, a lifeline) immediately available and be trained in its use.

– Hold a basic first aid certificate. – Can do Cardiopulmonary Resuscitation (CPR).

8.4.1 What are some emergency response precautions?


• The detailed plan for emergency response to an injury or other emergency within the confined space should be described in detail in the Confined Space Hazard Assessment and Control Program.

• Rescue the victims from outside of the confined space, if possible. No other worker should enter a confined space to attempt a rescue unless that worker is fully trained in the rescue procedures and is wearing the appropriate personal protective equipment. More than 60% of deaths in confined spaces are would-be rescuers, who are not fully trained and adequately equipped.

• Another worker qualified in confined spaces rescue procedures must be present outside the confined space before the first rescuer enters the confined space. Do not use the same air as the confined space workers you are rescuing. Wear SCBA (self contained breathing apparatus) or supplied air respirator with an escape bottle.

8.4.1 What are some emergency response precautions?


9. Personal Protection Equipment (PPE)

• PPE is traditionally regarded as the last line of protection with the emphasis being placed on avoidance and appropriate managerial control methods. However, the potentially hazardous nature and isolated position of those entering a confined space means that, for the surveyor, PPE may be the first line of protection.

• Each confined space will present different hazards and degrees of risk to health and safety, the final provision of PPE should therefore be based on an assessment of risk.

• As a general rule the following guidance is offered:

– Basic surveyor PPE should include:– Body protection (hard wearing overalls with suitable pockets for notebook, etc);– Foot protection (steel toecaps (200 joules), steel midsoles, good grip, oil resistant);– Head protection (hard hat with chinstraps);– Hand protection (hard wearing gloves);– Eye protection (protective glasses, goggles);– Ear protection (ear defenders or ear plugs – worn subject to communication system);– Gas meter - multi-gas meter for measuring of HC, H2S, CO, O2 is recommended;– Lighting (hand held with lanyard and appropriate beam width).


• Clean Respirators by disassembling / washing in warm water and mild detergent.

• Store mask and cartridges in ziplock bags.• Use a locker to store respirators and cartridges.

9.1 Maintenance of PPE


• Yes, appropriate training is extremely important to working safely in confined spaces. Hands-on training should be an essential part of the confined space training.

• Every worker that enters a confined space must be fully trained on the following:

– Recognition and identification of potential hazards associated with the confined spaces that will be entered.

– Evaluation and control procedures for the identified or potential hazards. – All equipment such as ventilation equipment (blowers), harnesses and air

quality monitors (e.g., Oxygen/combustible meters) that will be used while in the confined space.

– All personal protective equipment (e.g., respirators) that the worker will be using while in the confined space.

– All procedures for entering the confined space as outlined in the employer's Confined Space Hazard Assessment Program.

– Procedures to follow in the event of a situation developing that could present additional risk to the worker or an emergency.

– The specific work to be done while in the confined space.

10. Is worker training important?


• Workers with emergency rescue responsibilities will need additional specialized training.

• All confined space training should include some hands-on training with the safety equipment including the personal protective equipment and safety harnesses.

• Rescue procedures should be practiced frequently so there is a high level of proficiency.

• Employers should keep records of all confined spaces training including refresher courses.

10. Is worker training important?


11. Potential Hazards Overview

Engulfment Hazards

Loose, granular materials stored in bins and hoppers - grain, sand, coal, etc.

Crusting and bridging below a worker.Flooding of confined space.Water or sewage flow.Shifting liquid or solid substance that traps employee

Temperature ExtremesExtremely hot or cold temperatures.Steam cleaning of confined spaces.Humidity factors.Extremely cold liquids.Work processes inside the confined space can increase temperature extremes.Personal protective equipment.

Too much or too little

Oxygen Hazards


Toxic Hazards

Gases, vapors or fumes (examples: hydrogen sulfide, sulfur dioxide, carbon monoxide)

Flammable or Explosive Hazards

Vapors or dusts in concentrations large enough to ignite

Configuration

Walls or floor which slope downward or taper in can trap an employee

Physical Hazards

Contact with mechanical or electrical equipment, steam or other sources of heat, moving parts, energy.



Noise– Amplified due to acoustics within the space.– Damaged hearing, affect communication.

Slick / Wet Surfaces– Slips and falls.– Increased chance of electric shock.

Falling Objects– Topside openings expose workers inside confined space to falling objects.

Crushing


Special Hazards


1. Lack of organizational safety• Insufficient rescue measures • missing stand by person• Non existing work permit system

2. Lack of isolation3. Oxygen deficiency / Oxygen excess4. Limited entry / exit5. Danger due to electrical powered tools6. Electricity7. Radiation8. Hot or cold surfaces / mediums9. Hazard chemical substances10. Bad air out and NO fresh air in

Additionally to be considered:

• Increased physically work loads• Chemical reactions• Fire / explosions• Noise• Fall


Example of possible hazards while working in a confined space:


Other Hazards


Other Hazards


So, WHEN IN DOUBT, STAY OUT


Confined Space Quiz

1) A confined space means a space that: A) Is large enough that an employee can enter and

perform work B) Has limited or restricted means for entry or exit C) Both A&B D) None of the above


Confined Space Quiz

2) Examples of confined spaces are: A) Storage tanks, pits, silos, and vats B) Tunnels, sewers, shafts, and exhaust ducts C) Offices, carpools, and shopping stores D) A&B


Confined Space Quiz

3) True or False: The employee must assess the workplace to

determine if hazards are present that necessitate the use of PPE.


Confined Space Quiz

4) Which are examples of permit space hazards? A) Hazardous atmosphere, engulfment,

electrocution, and heat stress B) Storage tanks, pits, silos, and vats C) Tunnels, sewers, shafts, and exhaust ducts D) None of the above


Confined Space Quiz

5) What are some ways of reducing risks of hazards? A) Post signs and use of barriers B) Develop and use a written program C) Conduct monitoring and ventilate, eliminate, or

control the hazards of the confined space D) All of the Above


Confined Space Quiz

6) Which of the following are required on a confined space permit?

A) Permit space, purpose, date, and authorized entrants

B) Hazards of space, control methods, acceptable entry, and results of entry

C) Rescue and emergency services, communication procedures, and equipment

D) All of the above


Confined Space Quiz

7) True or False: In the preparation of a permit space, you must notify

all affected departments, post signs and barriers to protect entrants, and empty the confined space of any hazardous materials.


Confined Space Quiz

8) In the preparation of permit space, you must:A) Blind or disconnect and cap all input linesB) Verify breathing safety by air testing and add

emergency control telephone numbers C) All the aboveD) None of the above


Confined Space Quiz

9) True or False: During atmospheric testing, you must evaluate heat stress potential and control any hazards before entry but need not evacuate the space if the air becomes hazardous.


Confined Space Quiz

10) During atmospheric testing, you must:A) Continuously test and monitor air in all areas

before entryB) Make sure that the oxygen content is between 19.5 and 25.5 percentC) List any toxic materials that could be present

and their permissible exposuresD) A&C


Confined Space Quiz

11) Regarding safety procedures entering a confined space, which of the following applies:A) Authorized entrants can enter a permit space only after tested and found safeB) Each assigned entrant has to know what equipment to use and how to use itC) Do the task as quickly and efficiently as possibleD) All the above


Confined Space Quiz

12) Duties of the entry supervisor include:A) Verification of the permit and checks the condition

of the confined spaceB) Sees that unauthorized people are removedC) Cancels the permit when work is doneD) All the above


Confined Space Quiz

13) Duties of the Stand-by person include:A) Maintaining an accurate account of who’s

in the space, monitors activities of the space, and stays in touch with the entrantsB) Keeps unauthorized persons away from an occupied

permit spaceC) Orders the evacuation from the permit space and

summoning rescue when neededD) All the above


Confined Space Quiz

14) Duties of the entrant include:A) Knowing the hazards of the space and signs of exposureB) Follows their personal protective equipment training and keeps in contact with the attendantC) All of the aboveD) None of the above


Confined Space Quiz

15) True or False: Only workers trained in rescue can enter the space for the purpose of rescue whether an attendant is present or not.

Corporate Health and Safety ArcelorMittal

Documents

confined space procedures

confined spaces6

confined spaces1

confined space entry

rex atmospheres

toxic atmospheres

enclosed space

isolation of space