Confined Spaces/Vessel Entry Gas Testing -
OPITO Unit AGT1

1 Introduction to the course

Purpose of the Training Course
Summary of each classroom-training module
Summary of the practical session undertaken both in the classroom and in the workplace

2 Properties of flammable and toxic gases

Flammable gases: A study of the physical properties of:

(A) Natural Gas
(B) Propane
(C) Butane
(D) Crude Oil Vapours
(E) Solvents
(F) Hydrogen

Assessment for each regarding:

• Explosive limits
  
• Gas cloud formation
  
• Movement of gas clouds
  
• Densities of pure gases
  
• Gas dispersion
  
• Densities of gas clouds
  
• Effects of ventilation
  
• Autoignition temperature
  
• Flash point

Autoignition temperature

Toxic gases: A study of the toxic/hazardous characteristics of:

(A) Oxygen Deficiency and Enrichment
(B) Carbon dioxide
(C) Carbon monoxide
(D) Specialist materials, paints, solvents, condensate vapours, liquid nitrogen, chlorine, crude oil vapours and sludges.

Understanding the differences between asphyxiating and toxic gas atmospheres and assessment when appropriate of the following factors:

Toxic effects on the body
Exposure limits and the COSHH Regulations
Workplace Exposure Limits: 8 Hour Limit, 15 Minute Limit, Definitions and units of measurement

Hydrogen sulphide:

Occurrence in the clients industry, including micro- biological generation in waste water
Toxic properties, Workplace Exposure Limits, 8 Hour and 15 Minute Limits and the COSHH Regulations - EH40
"Take Note - and Remember!"
Safe operating practices
Important physical properties

3 Gas Sensors

Flammable gas sensors: Catalytic gas sensors - how they work and what causes them to become unreliable and fail, catalytic "poisons" and "inhibitors", the effects of silicones, Halon, water and other contaminants,"ambiguity" effects at high gas concentrations - thermal conductivity sensors used for inert gas purging operations - infra-red gas detection.

Nitrogen purging : Thermal conductivity detectors, calibration and use in purging operations, purge limit values calculated from triangularity graphs, direct/indirect purging, slug, displacement, pressure purging calculations, hazards, flow rates, stratification, condensate problems.

Toxic gas sensors: Electrochemical cells and other sensing methods for the detection of oxygen, carbon monoxide, chlorine and hydrogen sulphide, how they work and what causes them to become unreliable and fail.

4 The clients range of gas detectors

The Portable Gas Detector, description of your detectors, explanation of readings obtained, pre-issue testing, accessing 'auto zero' and 'peak hold' features, sources of error and malfunction and how to both recognise and reduce instrument failures - using for demonstration purposes, one example of each gas detector and sampling system

5 Use of chemical stain detector tubes

5.1 Using the Draeger/Kitagawa/Gastec gas detector for H2S, CO, CO2 and other toxic gas measurements.
5.2 Most frequent problems with chemical detector tubes

6 Certification for hazardous areas

6.1 The certification label and its location; Thermite sparking and static hazards
6.2 Gas Detectors, repair and maintenance rules

7 Confined spaces

7.1 Definition of Confined Spaces with examples, incident videos
7.2 Types of hazard that occur in Confined Spaces: Rust, Sludges, Simple and Complex Spaces

8 Legalisation regarding confined space entry

8.1 The Factories Act 1961 - Section 30; The Health and Safety at Work Act 1974 - Section 2
8.2 The Confined Spaces Regulations 1997: SI 1713
8.3 The Shipbuilding and Ship Repairing Regulations 1960

9 Written multiple-choice question assessment test

Results of 'closed books' MCQ assessment test and discussion

10 Practical session in classroom and on-site

Hot work
10.1 Understanding the methodology of gas testing - the "Thinking Process"
10.2 Explaining the Hot Work Assessment Criteria and competency assessment
10.3 Preparing the hot-work gas detector for use
10.4 Practical gas testing on-site for both gas and condensate leaks - evaluation of trainee competency against defined assessment criteria by means of observation and questioning.

Confined Space / Vessel Entry
10.5 Briefing the trainees and explaining the Confined Space Entry Competency Assessment Criteria
10.6 Preparing the vessel entry gas detector(s) for use
10.7 Vessel atmosphere testing and evaluation of trainee competence against defined assessment criteria by means of observation and questioning at the entrance to a typical confined space, simulation and/or inspection of output
10.8 Correct response to hazardous gas scenarios using 'flash' cards.

11 De-brief from practical session

End.