HVACR311 – Electrical for Refrigeration International Mechanical Code Relating to Refrigeration

International Mechanical Code IMC is broken down into chapters and sections. The chapters and sections are in numerical order. It is important for you to be able to quickly identify chapters and sections when you are looking for something.

Chapter 11 of IMC 2003 Governs the installation, design, construction and repair of refrigeration systems that use the vapor/compression refrigeration cycle. Governs piping, pressure vessels, pressure relief devices.

Chapter 11 of IMC 2003 Permanently installed devices are considered part of the system they are attached to.

Factor Built Equipment Factor built equipment meeting UL 207, 412, 471, or 1995 requirements and are self contained are considered to meet code if installed and serviced in accordance with manufactures directions.

Protection All components of a refrigeration system that could be damaged must be protected in an approved manner.

Water Connections Water connections to a refrigeration system must be made in accordance with this code and International Plumbing Code.

Fuel Gas Connections Fuel gas connections for refrigeration systems must be made in accordance with International Fuel Gas Code as well as International Mechanical Code.

Maintenance Mechanical refrigeration systems must be maintained in proper operating conditions and free from excessive oil, dirt, waste, excessive corrosion, other debris and leaks.

Section 1102 Section 1102 of the IMC describes the system requirements Says refrigerants can not be mixed Talks about refrigerant purity Talks about recovery Talks about reclaiming refrigerants.

Section 1103 Section 1103 talks about refrigerant system classification. Starts with and occupancy classifications.

Section Occupancy Institutional – disabled, debilitated, or confined occupants that can not readily leave. Public assembly – large numbers of people who can not quickly leave. Residential – permanent provisions for sleeping, eating, cooking, and sanitation.

Section Occupancy Commercial – Transact business, receive and ship goods, receive personal service and food. Large mercantile – over 100 persons congregate above and below street levels to purchase merchandise.

Section Occupancy Industrial – Not open to the public. Access to authorized persons are controlled. Used to manufacture or store goods such as chemicals, food, ice, meat, or petroleum. Mixed Occupancy – occurs when two or more classifications come together.

Section System Classification Systems are classified based on the probability of refrigerant leaks. –Low probability systems –High probability systems –See table for classifications and refrigerants.

Section 1104 Talks about maximum allowable refrigerant quantities. See table for guides. Talks about requirements for mechanical rooms.

Section Gives definitions for volume calculations. Noncommunicating spaces are neighboring rooms or spaces that do not have any permanent openings connecting them and do not share an HVAC system.

Section Communicating spaces do share a permanent opening and share an HVAC system. Air can easily move from one location to another. Plenums – When the area above a ceiling is used as a supply or a return plenum these areas are included in the volume calculations.

Section 1105 Section 1105 talks about machinery rooms and the requirements for leak detection, ventilation and shared use.

Section 1105 Refrigerant detectors must be installed per International Fire Code. Open flames from fuel burning appliances are not allowed unless combustion air is ducted from outside.

Section Ventilation Mechanical ventilation must be provided unless the mechanical room has adequate free openings. Mechanical ventilation must not discharge air closer than 20 feet from property lines and building openings. Makeup air must be provided to replace exhaust air.

Section Quantity Under normal conditions the mechanical ventilation system must exhaust the larger of: –.5 cfm per square foot of mechanical room area. –A volume required to limit room temperature rise to 18 degrees F. taking into account the ambient heating effect of all machinery in the room.

Section Under emergency conditions (refrigerant leak or fire) the ventilation system must exhaust the air according to the following formula: Q = 0.07 x √G Where Q = CFM’s and G is refrigerant in pounds of the largest system in the mechanical room.

Section Termination of relief devices inside the mechanical room must be above grade, outside structure and no less than 15 feet from other grade levels and not less than 20 feet from any window, ventilation opening or exit.

Section 1106 Covers mechanical room special requirements.

Section 1107 Piping This section covers refrigerant piping. All piping must be installed in accordance with this section. Primary purpose of this section is to prevent leaks and damage to pipes.

Section Types of pipe materials –Steel –Copper and Brass –Copper tubing –Copper tubing joints – must be brazed, not soldered. –Aluminum tubing

Section If joints and tubing are put into air ducts (DON’T DO THIS!!!) they must be able to withstand leaks at 150% higher than rest of system or any pressure relief setting.

Section Liquid receivers must be installed on all systems with 100 pounds or more of refrigerant.

Section 1108 Section 1108 talks about pressure testing refrigeration systems. The primary purpose of this section is to prevent leaks. Tests should be completed on both low and high pressure sides of system. Must be done with an inert gas such as nitrogen. Does not change pressure with temperature.

Section 1109 Speaks to periodic testing requirements. Testing must be performed on the following upon request from a code official: –Treatment and flaring systems –Devices needed to operate the equipment –Fans and associated emergency ventilation systems –Detection and alarm systems

Notes on Code International Mechanical Code is used in Connecticut. The BOCA code is used in MA. Each town or municipality has the right to add requirements to the code. Remember EPA requirements as well.

Notes on Code The CT licensing exam is open book and you will be given a list of code books to bring. Make sure you have the correct version. Current CT code is Update your code books every time a new version comes out.