Refrigeration Plant Safety Overview

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Questions and Answers

What defines a high-probability refrigeration system?

Refrigeration components are isolated from occupied spaces.

Refrigerant can leak into occupied spaces due to component failure. (correct)

Systems operate at low pressures under 100 kPa.

They use refrigerants that are non-toxic.

Which example represents a low-probability refrigeration system?

Direct expansion systems in warehouses.

Chilled water systems in commercial buildings. (correct)

Meat packing plants using open refrigeration.

Cooling coils fed directly with refrigerant.

Which of the following pressures defines a high-pressure refrigeration plant?

Pressure between 70 and 90 kPa.

Pressure greater than 100 kPa. (correct)

Pressure greater than 150 kPa.

Pressure below 50 kPa.

What is a characteristic of indirect systems in refrigeration?

They have refrigerant-containing components effectively isolated. Signup and view all the answers

Why are industrial facilities less of a hazard to the public?

Access is restricted to authorized personnel. Signup and view all the answers

What is one of the aspects that must be inspected during the visual inspection of refrigeration equipment?

Corrosion Signup and view all the answers

In which type of system could refrigerant leak due to HVAC failures?

High-probability direct expansion systems. Signup and view all the answers

What is a common refrigerant used in low-pressure refrigeration systems?

R-123. Signup and view all the answers

Which of these methods is NOT used for detecting refrigerant leaks?

Infrared thermal camera Signup and view all the answers

What is the significance of operator requirements for refrigeration plants?

They are not always required for low pressure plants. Signup and view all the answers

What kind of damage can air-cooled condensers sustain?

Damage from fan blades or bearings Signup and view all the answers

What should be done before taking apart any piping connection in a refrigeration system?

Test for refrigerant at a vent Signup and view all the answers

Where do leaks primarily occur in refrigeration systems?

At joints and connections Signup and view all the answers

What type of damage can chillers experience if the fluid is brine?

Accelerated corrosion Signup and view all the answers

Which method provides clear visibility of escaped refrigerant during leakage testing?

Sulfur candles Signup and view all the answers

Which of the following is a requirement for the visual inspection as per CSA B52?

Looking for insulation damage Signup and view all the answers

What critical elements are necessary for effective emergency response by Power Engineers?

Site-specific training on equipment operation Signup and view all the answers

Which of the following refrigerants is more toxic than the other?

R-717 is more toxic than R-123 Signup and view all the answers

What defines a high leak probability refrigeration system?

Systems with a history of frequent leaks Signup and view all the answers

What is the maximum alarm set point for an ammonia vapor detector?

3 PPM Signup and view all the answers

Why is a maintenance 'buddy' required to have ready access to water?

For immediate first aid in case of ammonia exposure Signup and view all the answers

What is a 'dead man valve' and its purpose?

A valve that only operates when actively held open Signup and view all the answers

What should be done if a person is trapped by an ammonia leak?

Evacuate the area immediately Signup and view all the answers

What is one potential hazard in refrigeration plants?

High-pressure liquid release Signup and view all the answers

What is the maximum allowable setting for the pressure-limiting devices in ammonia compression refrigeration systems according to CSA B52 code?

90% of the system high-side design pressure Signup and view all the answers

Why must the high-pressure limit control be connected to the compressor discharge pipe before the isolation valve?

To ensure the device can trip and function effectively Signup and view all the answers

What happens when the pressure-limiting device in a refrigeration system trips?

It shuts off the compressors and requires a manual reset Signup and view all the answers

What is the primary function of safety valves in refrigeration systems?

To protect pressure vessels and piping from damage Signup and view all the answers

What is a significant risk associated with positive displacement compressors?

They may develop sufficient pressure to rupture their casings Signup and view all the answers

In relation to environmental safety, how should refrigerant be handled during a malfunction?

It should be contained within the system whenever possible Signup and view all the answers

What is the function of a pressure-relief valve installed on a compressor?

To protect the compressor by releasing excess pressure Signup and view all the answers

Where do safety valves installed on ammonia compressors typically discharge?

To the low-side of the system Signup and view all the answers

What is a key design rule for ammonia refrigeration systems?

No flame-producing devices should be located where a leak could occur. Signup and view all the answers

Where must direct ammonia refrigeration systems be installed?

In industrial occupancies only. Signup and view all the answers

What is one requirement for ammonia refrigeration system machinery rooms over 75 kW?

They must meet Class T machinery room standards. Signup and view all the answers

Which statement about indirect ammonia systems is true?

They are commonly used in curling rinks and hockey arenas. Signup and view all the answers

What is the purpose of installing ammonia detectors in refrigeration systems?

To provide warnings at high ammonia concentrations. Signup and view all the answers

What construction feature is required for areas containing ammonia refrigeration system machinery?

They must be of tight construction with tight-fitting doors. Signup and view all the answers

What distinguishes direct ammonia systems from indirect systems?

Direct systems must have stricter safety measures in industrial settings. Signup and view all the answers

Which of the following refrigerants is commonly used in indirect systems for rinks and arenas?

Ammonia. Signup and view all the answers

What is the maximum temperature for permanent hot surfaces in a machinery room?

427°C Signup and view all the answers

What is required for the ventilation system in machinery rooms?

Mechanical ventilation with power-driven fans Signup and view all the answers

What must be installed outside the machinery room regarding fan switches?

Switches that can start but not stop the ventilation Signup and view all the answers

At what ammonia concentration must a vapour detector actuate an alarm and start the ventilation system?

300 ppm Signup and view all the answers

Where should vapour detectors be located in a machinery room?

Locations where refrigerant leaks would have maximum concentration Signup and view all the answers

What must be provided outside the machinery room for emergencies?

A machinery shutdown switch Signup and view all the answers

What type of warning system is included with the ammonia leak detection system?

Alarm horn and alarm beacons Signup and view all the answers

What type of panel is used for ammonia leak detection?

Digital readout control panel Signup and view all the answers

Study Notes

Refrigeration Plant Safety Learning Outcomes

Students will be able to outline potential hazards in refrigeration plants.
Students will be able to describe CSA requirements to mitigate hazards.
Students will be able to describe typical responses to significant refrigerant leaks.

Refrigeration Plant Safety Learning Objectives

Identify and explain CSA B52 Code requirements for refrigeration plant machinery rooms.
Identify safe practices in refrigeration plant operation and maintenance.
Describe appropriate emergency response to significant refrigerant leaks.
Detail Canadian Environmental Emergency Regulations in relation to refrigeration plants.

Chapter Introduction

Jurisdictions regulate large refrigeration plants under the authority of Power Engineers.
Potential hazards include pressure vessel/piping explosions, combustion explosions, asphyxiation, cardiac arrest, chemical burns, and freeze burns.
Chemical reactions are another possible hazard.
This chapter covers safety features, safe operation, and maintenance, as well as emergency responses to refrigerant leaks.

Objective 1: CSA B52 Code Requirements

Toxicity and flammability of refrigerants vary.
Ammonia (R-717) is toxic over 0.03% by volume in air.
R-123 is toxic over 0.1% by volume in air.
Propane (R-290) is more flammable than R-717.
R-717 has an explosive range between 15% and 28% in air.
R-290 has an explosive range between 2.1% and 9.5%. R-717 leaks are easier to detect.
Some refrigerants are denser than air. Large leaks displace air.
Refrigerant changes might change machinery room requirements.
R-11 (ozone depleting) was often replaced with R-123 (toxic).

Objective 2: Safe Practices in Refrigeration Plant Operation and Maintenance

Ammonia is corrosive and highly soluble in water.
Tissue contact damages from ammonia can lead to chemical burns.
Inhalation exposure damages the lungs.
Leaks in ammonia systems can result in caustic white cloud, which should not be entered.
Ammonia boils at −33°C.
Ammonia exposure can cause frostbite, burns, and chemical burns.
Maintenance procedures like draining oil pots, adding oil, and purging non-condensables should be performed with designated personnel and appropriate safety equipment.
Work practices include disassembly, hot work and leak checks.
Refrigerant storage should be a safe distance from flames or hot surfaces.
Emergency handling and response plans are essential.

Objective 3: Emergency Response to Significant Refrigerant Leaks

Employers must provide suitable PPE and respirators.
Plants must have procedures for worker roles, lines of authority, training, and communication protocols.
Site-specific emergency plans are needed.
Trained personnel should handle leaks, evacuate the area, and implement emergency procedures.
People should not enter ammonia vapour clouds.
First aid procedures for ammonia exposure are necessary
Exposure can lead to serious health consequences, and immediate medical attention is crucial.

Objective 4: Canadian Environmental Emergency Regulations (E2)

CEPA (Canadian Environmental Protection Act) establishes rules for environmental emergencies.
E2 regulations aim to protect human life and the environment in situations like a release from refrigerants .
Specific requirements include plans, training, and procedures for ammonia emergency responses.
A plant must have a plan for leaks with 4.5 tonnes of ammonia or more and location.

Chapter Summary

Jurisdictions regulate refrigeration plant care and operation.
Safe operation and maintenance procedures reduce potential hazards.
Comprehensive emergency plans are critical.
Personnel and site-specific procedures for maintenance and emergencies are vital.

Knowledge Exercises (Examples)

Factors determining refrigeration system hazard levels.
Comparing toxicity of different refrigerants (like R-123 and R-717).
Comparing risks for occupants in various building types.
Understanding high versus low leak probability systems.
Ammonia vapour detector maximum alarm settings.
Potential hazards in refrigeration plants.
Determining whether an alarm should be activated by a detector (and why).
Extra precautions for institutional settings during ammonia leaks.
Explanations of "dead man valve" function, location, and purpose.
Importance of readily available water for maintenance personnel.
Details of IIAR labelling requirements for ammonia piping.
CEPA and E2 regulations, for understanding environmental emergency responses.

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Description

This quiz covers essential safety protocols and regulations related to refrigeration plants. Students will learn about CSA requirements, potential hazards, and emergency responses to refrigerant leaks. Prepare to identify safe practices and understand environmental regulations in the context of refrigeration.