Occupational Hygiene Management OCHY302

Occupational Hygiene Management

Task details and instructions

Use of artificial intelligence (AI)

The use of generative AI is not permitted for this assessment. This includes but is not limited to tools like Microsoft Copilot or ChatGPT (please see What is Artificial Intelligence? if you are not sure). All submitted work must be your own original content, created without the aid of generative AI. Failure to adhere to this policy may constitute academic misconduct and result in serious consequences. If you have been advised to use a specific tool as part of a personal learning plan, you should continue to use it.

• The word count for this assessement is 3000+/- 10%

• In the report, every page must be numbered in the footer. In the header of every page, you must put your student number Do not include your name in the assignment.

• All figures and tables must be numbered and have an appropriate, detailed caption. The number and caption should be present above the tables and beneath the figures.

• Support the arguments with references to peer reviewed articles and publications such as industry and technical reports

• Do not cite or reference lecture notes in your

• Do not use direct quotations in written Quotations do not belong in academic scientific writing.

• You should use Cite Them Rite Harvard referencing style please see link http://libguides.mmu.ac.uk/refguide/mmuharvardfor guidance.

• The assignment should be divided into sections as detailed in the assessment task below.

If you are unable to meet the deadline for submission, please refer to the MMU Assessment Regulations for Taught Postgraduate Programmes, as it details the Universitys policy on the late submission of coursework. Please note if you have mitigation and evidenced extensions you will need to refer to the Universitys Procedure on Extensions.

Situation to be studied.

High Energy Petroleums main business activity is storage and distribution of petrol (gasoline). However, it does operate a small refinery. This exercise involves a maintenance task which occurs periodically the cleaning of leaded product storage tanks.

Tetraethyl lead (TEL) is an alkyl (or organic) lead compound [(C2H5)4 Pb] and is used to raise the octane number of gasoline to prevent knocking in internal combustion engines. The concentration of lead alkyl in gasoline varies but is typically around 0.2 0.4 g/L. TEL is blended into gasoline at the refinery through automatic injection systems and hence TEL handling in a refinery does not usually pose an exposure risk except in the case of leaks or spillages.

Gasoline (petrol) is stored at refineries and distribution terminals in various size tanks typically 10-15 metres high and 2030 metres in diameter (photograph 1). Periodically these tanks have to be emptied and cleaned of sludge, which accumulates on the bottom of the tank, and rusty scale which forms on the inside lining of the tank. The cleaning of tanks used for leaded product is potentially hazardous owing to the presence of flammable and toxic vapours, including lead and hydrocarbons.

Once the tank has been cleaned it is inspected both visually and with xray equipment and any repairs carried out. This can involve the grinding and welding of steel plate. If the tank is to be taken out of leaded service it must also be grit blasted and epoxy lined. This prevents the leaching out of organic lead which has been absorbed into the floor and wall of the tank. Tanks which have contained leaded product at some time in the past and have since been used for other nonleaded products, and which have not been epoxy lined, may give off toxic vapours even after several years in nonlead use.

In the situation under study, a floating roof storage tank 10.6 metres high and 19.5 metres in diameter was used for a number of years for leaded gasoline. It was to be emptied, cleaned, descaled by grit blasting, inspected, repaired (if necessary) and coated internally with a twopack polyurethane paint.

Note: A floating roof floats on top of the product to prevent loss of vapours during filling. As the product is removed from the tank the roof falls until it rests on legs 1.7 metres from the tank floor.

This tank has two 90 cm diameter manholes (photograph 2) located diagonally opposite each other and positioned about 0.5 metres above ground level

(Source: D Rhodes reproduced with permission)

During the course of the maintenance exercise the following work procedures were followed.

1. The tank is emptied of product down to a level where the viscosity of the sludge prevents further removal through pipework (usually about 30 cm from floor).

1. All product lines to and from the tank are

1. Both manhole covers are unbolted and

1. Tank left to ventilate naturally for a couple of

1. A 610 mm diameter axial flow extraction fan is mounted in one of the manholes and let run for 24 hours (at the static pressure of 37 Pa the fans capacity is 10,000 m3/hr).

1. With the fan still running, a terminal operator ensures the atmosphere is less than 5% of the Lower Explosive Limit (LEL) before taking a sludge sample. The terminal operator enters the tank with a well maintained full face air supplied breathing apparatus (BA). Airlines to the apparatus are solvent resistant. Protective clothing includes rubber boots, PVC gloves and impervious full suit. Urinary leads before and after check OK.

1. Laboratory analyses shows sludge to comprise:

* Gasoline however can contain up to 5?nzene which has an exposure standard of 0.5 ppm (1.6 mg/m3). Benzene is slightly more volatile than gasoline (petrol).

8. A work permit is raised to allow four contractors to begin removing sludge under the charge of the contractor supervisor. The sludge is shovelled into open pales and handed through the manhole and emptied into an open skip for transportation off site. PPE requirements on permit for those inside the tank include Tyvek impervious coveralls, airsupplied BA, PVC boots and gloves.

Air supply is from a diesel-powered air compressor located outside the tank adjacent to the skip (the respirator airlines supplied by the contractor were subsequently found to be of poor quality PVC and which were showing signs of wear). Rests and meal breaks were taken in a construction shed adjacent to the tank. The temperature during the day rose to 33 with little air movement.

9. All four presented themselves for prework urinary leads with results normal. At the end of the day samples 1 and 2 were taken; samples 3 and 4 had to be taken the following afternoon as the contractors had failed to present themselves to the medical The first two gave readings of 87 g/litre and 110 g/litre. The two samples taken from the workers the next afternoon were well within the normal range.

10. Upon the removal of the sludge the tank floor was water washed and dried. There were some isolated small puddles of gasoline remaining on the Tests for oxygen content, lead in air and explosivity were conducted by a plant operator wearing airsupplied BA. Inspection revealed the need for a number of floor plates to be welded.

Note 1. The lower explosive limit (LEL) for gasoline is about 1.4% (14,000 ppm). 5% of the LEL is used by the oil industry as a limit above which no hot work such as welding is permitted.

2. There is no suitable personal sampling system for alkyl lead. The method involves absorbing the lead into cyanide solution followed by chemical reaction and colorimetric determination.

11.Based on the above results the extraction fan was turned off and the decision was made that airsupplied respiratory protection was no longer Organic respirators were made available but there was no record of who used them. As a precautionary measure a static leadinair monitor was set up just inside the tank approximately 10 metres from where the welding was to take place. Readings were taken every 1.5 hours during the welding (takes about one hour to obtain a sufficient sample)

12. An oxygen monitor with alarm set at 20% was located adjacent to the welding 13. Three metal trades personnel, including one welder, spent seven hours inside the tank. The welder had a visor to prevent flash burns, cotton overalls and other welding protective clothing. All three provided urine samples prior to commencing work and again at the end of the day. Normal rest breaks and lunch were taken.

14. Once the tank is cleaned it is ready to be grit blasted using a garnet/slag material. Workers agree to be monitored for personal exposure to dust and lead. The rust and scale to be removed has a lead content of 0.5%. Dust samplers were worn for five hours to sample inhalable dust according to statutory requirements. The dust fraction collected on the filter was 0.2 mg and the flowrate was 2.0 L/min.

Assessment information

Part One: Please write an individual report in the following format: Executive Summary, Introduction, Main Body (which are the issues listed below) and Conclusion. The word count should be 2700 +/- 10% covering only the Introduction to Conclusion sections; Executive summary, tables and figures are not included in the word count.

Assessement tasks

The management has concerns regarding health and safety of the workers involved with the process and request you investigate the process. You are to produce a report with focus on the following issues:

1. Explain why is skin contact a source of exposure to TEL (Tetraethyl lead)? (300 words max).

1. In Table 2 why did samples 1 and 2 show elevated exposures but not samples 3 and 4? (200 words max)

3. Outline at least six hazards you believe a competent occupational hygienist should investigate in the described tank cleaning operation. (1000 words max)

3. If they were using breathing apparatus why were there elevated urinary leads (Table 2)? Explore all possible causes. (200 words max)

3. What do the static lead in air results tell you about the atmosphere inside the tank and the nature of the welders working environment? (300 words max)

3. Give an explanation why the urinary leads in Table 5 are elevated when the results in Table 4 indicate acceptable airborne lead levels? (300 words max)

Part Two: Reflective Assessment Element

Reflect on and critically appraise the policies and scientific strategies within the field of occupational hygiene, considering how these have influenced your understanding and approach to occupational health and safety in your professional or academic experiences. (300 words max)

Learning outcomes for this assignment

1. Appraise the policies and scientific strategies within the field of occupational

2. Critically apply the measurement and control strategies available for specific health hazards and risks to the workplace.

3. Evaluate the effectiveness of workplace control strategies for occupational hygiene management.

Graduate attributes developed though this assignment.

Interpersonal, Autonomous, sustainable & Enterprising Graduate attributes

Assessment Grading and Marking Rubrics