South Carolina - Air Conditioning

Key Concepts

Scope and identification (Section 401) - Chapter 4 governs piping from the point of delivery to the connections with the appliances (401.1). - For other than steel pipe and CSST, exposed piping shall be identified by a yellow label marked "Gas" in black letters, spaced at intervals not exceeding 5 feet; the marking is not required on piping in the same room as the appliance served. CSST is identified per ANSI LC 1/CSA 6.26 (401.5). - Where two or more meters supply separate consumers on the same premises, piping systems shall not be interconnected on the outlet side of the meters (401.6). Piping from multiple meter installations must be permanently marked so each meter's system is readily…

Source: Modern Refrigeration and Air Conditioning (20th ed.), Chapter 8

Key Concepts

Sizing (Section 8.1.1, ACR Copper Tubing; Figures 8-2 and 8-3) - ACR tubing size is designated by the actual outside diameter of the tubing. Copper water tubing is specified by nominal size equal to OD minus 1/8″. A 1/2″ ACR tube measures 1/2″ OD; a 1/2″ copper water tube measures 5/8″ OD. - Soft and hard-drawn ACR have the same outside diameters. Wall thicknesses are Type K (heavy wall) and Type L (medium wall); Type L is more commonly used.

Key Concepts

Burial and underground gas piping - Underground piping systems: minimum depth 12 inches (305 mm) below grade (IFGC 404.12). - Exception: individual lines to outdoor lights, grills and other appliances — not less than 8 inches (203 mm) below finished grade, provided the installation is approved and in a location not susceptible to physical damage (404.12.1). - Gas piping shall not penetrate foundation walls below grade; it must enter/exit above grade and the annular space be sealed (404.6). Zinc coating is not adequate corrosion protection for underground piping (404.11.1); dissimilar metals joined underground require an insulating coupling or fitting (404.11.3). - Plastic pipe: outdoors underground only, not within or under any building or slab, not over **100…

Key Concepts

Gas piping pressure testing (SC Fuel Gas Code 2021, Chapter 4) - Test pressure shall be not less than 1 1/2 times the proposed maximum working pressure, but not less than 3 psig, irrespective of design pressure (Section 406.4.1). Where test pressure exceeds 125 psig, it shall not exceed a value producing hoop stress greater than 50 percent of the specified minimum yield strength of the pipe. - Test duration shall be not less than 1/2 hour for each 500 cubic feet of pipe volume or fraction thereof. For a system under 10 cubic feet or a system in a single-family dwelling, duration shall be not less than 10 minutes. The duration **is not required to exceed…

Key Concepts

Drainage of underground ducts (Section 603.8.1). Ducts shall have a minimum slope per foot (10.4 mm/m) to allow drainage to a point provided with access. Underground ducts must be approved for underground installation, and metallic ducts not having an approved protective coating shall be completely encased in not less than 2 inches (51 mm) of concrete (Section 603.8). Ducts shall be sealed, secured and tested prior to concrete encasement or direct burial, and shall be leak tested as required by Section C403 of the International Energy Conservation Code (Section 603.8.2).

Key Concepts

Appliance shutoff valves — SC Fuel Gas Code 2021, Section 409.5 Each appliance shall be provided with a shutoff valve in accordance with Section 409.5.1, 409.5.2 or 409.5.3.

• 409.5.1 Located Within Same Room: valve shall be in the same room as the appliance, within 6 feet (1829 mm) of the appliance, and installed upstream of the union, connector or quick-disconnect device it serves, with access provided. Valves serving movable appliances (cooking appliances, clothes dryers) are considered accessible where installed behind such appliances.
• 409.5.2 Vented Decorative Appliances and Room Heaters: valves may be remote where provided with ready access, permanently identified, and not serving another appliance; piping from the valve to within 6 feet of the…

Exam: South Carolina – Air Conditioning | Topic weight: 1 question (1%)

Key Concepts

Gas piping identification and general (SC Fuel Gas Code 2021, Section 401) - For other than steel pipe and CSST, exposed piping shall be identified by a yellow label marked "Gas" in black letters, spaced at intervals not exceeding 5 feet (1524 mm). The marking is not required on piping in the same room as the appliance served; CSST is identified per ANSI LC 1/CSA 6.26 (401.5). - Where two or more meters supply separate consumers on the same premises, piping systems shall not be interconnected on the outlet side of the meters (401.6); multiple-meter piping shall carry approved permanent identification (401.7). - Where an…

Key Concepts

Wet-rotor circulating pumps. A wet-rotor centrifugal pump has bearings lubricated by the circulating system water rather than petroleum lubricant. The wet-rotor design eliminates the need for a shaft seal and reduces noise and maintenance. The impeller, terminal box, and system flow-control valves are all still required. (Section 39.1.2, p. 1039)

Air separator placement. Air separators and air scoops are placed downstream from the boiler and upstream from the circulating pump. At that point the circulating water is relatively hot and at relatively low pressure — the condition in which water holds the least dissolved oxygen — so separation is most effective. (Section 39.1.6, p. 1047)

SC Air Conditioning Exam | ~1 question (1% of exam)

Key Concepts

Insulation characteristics (SC Mechanical Code 1204.1). Pipe insulation installed in buildings shall conform to the International Energy Conservation Code; shall be tested in accordance with ASTM E84 or UL 723, using the specimen preparation and mounting procedures of ASTM E2231; and shall have a maximum flame spread index of 25 and a smoke-developed index not exceeding 450. Insulation installed in an air plenum shall comply with Section 602.2.1. Exception: the maximum flame spread index and smoke-developed index shall not apply to one- and two-family dwellings.

Required thickness (1204.2). Hydronic piping shall be insulated to the thickness required by the International Energy Conservation Code.

Exam: South Carolina – Air Conditioning | Topic weight: 1 question (1% of exam) Primary source: South Carolina Mechanical Code 2021, Chapter 6 (Duct Systems) and Chapter 12 (Hydronic Piping)

Key Concepts

Duct supports — the controlling standard (Section 603.10) "Ducts shall be supported in accordance with SMACNA HVAC Duct Construction Standards—Metal and Flexible. Flexible and other factory-made ducts shall be supported in accordance with the manufacturer's instructions." This is a two-part rule: rigid duct → SMACNA; flexible/factory-made duct → manufacturer's instructions.

Structural integrity of ducts (Section 603.1) "Ducts shall be constructed, braced, reinforced and installed to provide structural strength and durability." Section 603.1 also states the air distribution system shall be designed and installed to supply the…

South Carolina – Air Conditioning (1 question, ~1% of exam)

Key Concepts

Vibration isolation (ACCA Manual D, 3rd ed., Appendix 13, A13-10 "Provide Vibration Isolation," p. 189). The full recommended package is: - Blower wheels must be dynamically balanced. - Blowers and blower cabinets installed per the manufacturer's recommendations. - Vibration pads installed under equipment. - Flexible connections between the blower cabinet and the ductwork. - Flexible connectors for rigid conduit and piping connections. - Ducts supported and isolated in accordance with SMACNA Standards. - Whenever possible, locate HVAC equipment away from rooms that should be quiet.

South Carolina – Air Conditioning | 5 verified practice questions on this topic

Key Concepts

Boiling out a new system (initial start-up). Modern Refrigeration and Air Conditioning, Section 39.4.1 (pp. 1063–1064): to prepare a system for initial start-up, fill the system with water and add about one pound of trisodium phosphate for every 50 gallons of water, circulate the solution about four hours, drain it, clean the screens, and refill with water. This removes flux, cutting oil, and installation debris before the system is placed in service.

SC Air Conditioning · 2 questions (2% of exam)

Key Concepts

Heat transfer and heat loads. Heat always flows from hot to cold. Heat loss is transfer of heat from inside to outside by conduction, convection, and radiation through all surfaces of a house; heat gain is the increase of heat in a space from solar radiation and heat radiated by lights, equipment, or people (Modern Refrigeration & Air Conditioning, 20th ed., §37.1). The heat load is the amount of heat that must be added or removed to maintain the desired temperature; for sizing, the maximum heat load is determined for a period of one hour (§37.2).

Key Concepts

EPA Section 608 certification types. Type I — small appliances with 5 pounds of refrigerant or less; Type II — high- or very high-pressure appliances; Type III — low-pressure appliances; Type IV — Universal (covers I, II and III). Boiling points between –58°F (–50°C) and 50°F (10°C) at atmospheric pressure are high pressure; below –58°F is very high pressure; above 50°F (10°C) is low pressure. Type I, II and III exams are 25 core + 25 type-specific questions (50 total); Universal is 100 questions. Passing is 72% (18 of 25 per section); the Type I open-book test requires at least 84%. (Appendix G — EPA Certification Types, Pages 1567–1568)

Key Concepts

Design conditions. Manual J heating loads use the ASHRAE 99 percent outdoor dry-bulb values; the outdoor temperature is colder than the Table 1 value for 1 percent of total cold-month hours, about 85 to 90 hours per year (Manual J, Section 18-1; same language in Manual N, Section 4, "Winter Heating—99% Dry-Bulb"). Cooling uses the 1 percent dry-bulb (about 85 to 120 hours per year). Manual J/N default indoor values: 70°F for heating, 75°F dry-bulb / 63°F wet-bulb (≈75°F, 50% RH) for cooling (Manual J, Section 18-2; Manual N, Section 4, "Indoor Design Conditions"). Manual N wind defaults are 15 MPH heating, 7.5 MPH cooling (Manual N, Section 4, "Wind Speed").

Key Concepts

Manual J heating load is a "worst-case" procedure. Per Manual J Section 4-1 (Page 4-1 / PDF Page 41), the heating load estimate ignores three things, which simplifies the procedure substantially and provides a built-in safety factor: - Solar gain is ignored (benefit reduced by short winter days, cloud cover, long nights). - Thermal mass is ignored (benefits diminish during a string of very cold, very cloudy days simulating steady-state conditions). - Internal loads (occupants, appliances, lighting) are ignored — a conservative assumption.

Exam: South Carolina – Air Conditioning | Weight: Air Compressors — 1 question (1% of the exam) Source: Modern Refrigeration and Air Conditioning (20th ed.), Chapter 18

Key Concepts

Drive configurations (Section 18.1.2 — Hermetic Compressors) - In a hermetic compressor, the motor is sealed inside the same dome or housing as the compressor, so a shaft seal is not needed. The motor is directly connected to the compressor, often through a shared shaft. - Semi-hermetic units are enclosed in a bolted assembly and are also called field-serviceable or accessible. Several companies produce hermetic compressors of over 20 horsepower. - Fully hermetic compressors are sealed in a welded casing, cannot be serviced without cutting open the shell, and…

South Carolina – Air Conditioning | 2 questions (2% of exam)

Key Concepts

Airflow measurement instruments - A flow hood directs and calculates all of the airflow through a duct at a given supply or return; sensors read air velocity and air volume (Modern Refrigeration and Air Conditioning, Section 30.1.2, p. 789). - An air handler flowmeter is placed in the air stream of an air handler to measure the total airflow of a central system, and is typically sized to fit over a large return grille or in the space normally occupied by the air filter (Section 30.1.3, p. 789). - Instruments useful for airflow study include the manometer, barometer, pitot tube, anemometer, smoke (velocity/leak indicator), and hot-wire…

South Carolina – Air Conditioning | ~1% of exam

Key Concepts

Set point, range, cut-in, cut-out, differential - The differential is the difference between the cut-out value and the cut-in value. For a cooling system: cut-in – cut-out = differential. For a heating system: cut-out – cut-in = differential. Always subtract the lower value from the higher value (Section 16.2.2, Pages 355–357). - Example given in the text: a cooling system with cut-in 25°F (–3.9°C) and cut-out 15°F (–9.4°C) has a differential of 10°F, and the range is 15°F to 25°F (Section 16.2.2). - Range adjustment moves cut-in and cut-out both higher (or both lower) by the same amount. The range and average set point change, but the differential…

Key Concepts

Two diagram styles (Section 16.1, p. 352). HVACR technicians encounter two main styles: pictorial diagrams and ladder diagrams.

• Pictorial diagrams (16.1.1, p. 352): used primarily in service or installation manuals to show how to connect electrical devices in a unit. They let a technician trace wire connections (useful for finding a loose or omitted connection), show the approximate physical location of devices in a unit, and may give the colors of wires running to and from devices.
• Ladder diagrams (16.1.2, p. 352): two parallel power wires with rungs between them, like a ladder. They are "set up to reflect the order of component operation in a system. Devices near the top will be energized and…

Key Concepts

Multistage thermostats (Section 36.8.3, Page 966). Thermostats that have a W2 or Y2 terminal are considered multistage thermostats. In heating mode, a thermostat "will not close across terminals R and W2 until the temperature drops down below the set point by more than 3°F, in most cases." In cooling mode, "terminals R and Y2 will not close until the temperature rises above the set point by more than 3°F." These temperature separations between first and second stages are adjustable in many cases, so when troubleshooting a second-stage problem, adjust the thermostat far enough to close the correct terminals.

Key Concepts

When a machinery room is required. Except as provided in Sections 1104.2.1 and 1104.2.2, all refrigerant-containing components must be located outdoors or in a machinery room where the quantity of refrigerant in an independent circuit exceeds the amounts in Table 1103.1. For blends not listed, the same requirement applies where any blend component exceeds its Table 1103.1 amount, or where the combined blend components exceed 69,100 ppm by volume (Section 1104.2). Required machinery rooms are built per Section 1105 for Group A1 and B1 refrigerants, and per Sections 1105 and 1106 for Groups A2, B2, A3 and B3.

Key Concepts

Compression cycle and sides of the system. In the refrigeration cycle the low side begins at the opening of the evaporator just past the metering device; the compressor is the divider between low and high sides, and the metering device divides the high side from the low side. The low side absorbs heat; the high side rejects it (Ch. 6, Section 6.2, Page 91).

Comfort cooling range. Comfort cooling systems reduce temperature and humidity and often use mechanical refrigeration to maintain the high-temperature refrigeration range (between 55°F to 90°F). The refrigerant evaporating temperature of most comfort cooling systems is 40°F to 50°F (4°C to 10°C) (Ch. 31, Introduction).

Key Concepts

Basic operation (Section 40.1, pp. 1082–1083). A heat pump is a compression refrigeration system that reverses refrigerant flow to add or remove heat. A reversing valve controls flow direction. In heating mode, the outdoor coil is the evaporator and the indoor coil is the condenser; in cooling mode, the reversing valve shifts and the indoor coil becomes the evaporator, the outdoor coil the condenser. Although flow through each coil reverses, flow through the compressor is always in the same direction. A coil at 0°F (–18°C) still removes heat from outside air at 10°F to 15°F (–12°C to –9°C); compressed vapor rises to 120°F to 140°F (49°C to 60°C).

Exam: South Carolina – Air Conditioning | 2 questions (2% of exam)

Key Concepts

Gas vent termination (SC Fuel Gas Code 2021, Ch. 5, Section 503.6.5 / Figure 503.6.5) - For gas vents 12 inches or less in size located not less than 8 feet from a vertical wall, the minimum height (H) above the roof for a roof slope over 8/12 to 9/12 is 2.0 feet. - Chimneys and vents shall be sized in accordance with Sections 503 and 504 (Section 501.4). Every appliance shall discharge products of combustion to the outdoors, except appliances exempted by Section 501.8 (Section 501.2). Abandoned inlet openings shall be closed by an approved method (Section 501.5). Where a mechanical forced draft system…

South Carolina – Air Conditioning | 2 questions (2% of exam)

Key Concepts

Electric resistance heating principles (Ch. 43.1, p. 1194) - Electric resistance heating produces heat by conducting electricity across electric heating elements. Conversion: 1 watt = 3.413 Btu/hr; 100 watts = 341.3 Btu/hr; 1,000 watts (1 kW) = 3,413 Btu/hr. - Watt's law: P = I × E (power in watts, current in amperes, voltage in volts). - The kW figure obtained from a building's Btu/hr load is the minimum heat-producing capacity; the combined capacity of the installed elements "should meet or exceed this value."

Key Concepts

Appliance venting categories (Modern Refrigeration, Sec. 41.8, p. 1134) - Category I — negative vent pressure, noncondensing — Class B vent. - Category II — negative vent pressure, condensing — special vent material specified by the manufacturer. - Category III — positive vent pressure, noncondensing — stainless steel pipe. - Category IV — positive vent pressure, condensing — PVC. - Gas furnaces rated over 83% AFUE develop condensation in the heat exchanger or flue vent; those at or below 83% do not (Sec. 41.7, pp. 1131–1132). 78% AFUE is the federal minimum for new furnaces; 79%–83% is the mid-efficiency range. - Vent connectors for Category II, III and IV appliances shall be as specified for the venting…

Exam: South Carolina – Air Conditioning

Key Concepts

• General. Air for combustion, ventilation and dilution of flue gases for appliances installed in buildings shall be provided by one of the methods in Sections 304.5 through 304.9. Where Section 304.5 is not met, outdoor air shall be introduced per Sections 304.6 through 304.9. Direct-vent appliances, gas appliances other than natural draft design, vented gas appliances not designated Category I, and appliances with power burners follow the manufacturer's instructions (Section 304.1).
• Indoor combustion air (304.5). The total required volume is the sum of the required volumes for all appliances located within the space. Where the air infiltration rate is known to be less than 0.40 ACH, Section 304.5.2 shall…

Key Concepts

Scope of the piping provisions. The code's piping rules cover natural gas systems operating at 125 psig or less and LP‑gas systems at 20 psig or less, "except as provided in Section 402.7," and extend from the point of delivery to the outlet of the appliance shutoff valves (SC Fuel Gas Code 2021, §101.2.2). Chapter 4 governs design, installation, modification and maintenance of those systems (§401.1). LP‑gas storage is designed and installed per the SC Fire Code and NFPA 58 (§401.2). Section 101.2.4 lists systems outside the code (e.g., portable LP‑gas appliances not connected to fixed fuel piping, LNG installations, LP‑gas piping for railroad switch heating, temporary LP‑gas piping for construction).

Key Concepts

Scope and pressure limits (Chapter 1). Section 101.2.2: the code covers piping systems for natural gas with an operating pressure of 125 psig or less and for LP-gas at 20 psig or less, except as provided in Section 402.7. Coverage extends from the point of delivery to the outlet of the appliance shutoff valves.

Cold-weather LP-gas (402.7.1). LP-gas systems designed to operate below -5°F, or with butane or a propane-butane mix, shall be designed to either accommodate liquid LP-gas or prevent LP-gas vapor from condensing into a liquid.

South Carolina Air Conditioning Exam | Topic weight: 2 questions (2%)

Key Concepts

Scope and point of delivery - The code covers piping for natural gas at 125 psig or less and for LP-gas at 20 psig or less, except as provided in Section 402.7. Coverage extends from the point of delivery to the outlet of the appliance shutoff valves (Section 101.2.2). - For undiluted LP-gas, the point of delivery is the outlet of the service pressure regulator, exclusive of line gas regulators. The LP-gas service pressure regulator is the one upstream of all line gas regulators and downstream of any first-stage or high-pressure regulator (Chapter 2, Section 202 — "Point of Delivery"; "Regulator, Service Pressure"). - **Outside the…

SC Air Conditioning Exam

Key Concepts

Pressure units and blower performance - Residential air distribution pressures are typically less than 0.025 psi, so inches of water column (IWC) is used; 27.7 IWC = 1.0 psi, and 1.0 IWC = 249 Pa. Pascals are used for blower door and duct blaster testing (Manual D, Section 1-1). - Blower airflow decreases as resistance increases. The system operating point is the single intersection of the blower curve and the duct system curve (Manual D, Sections 1-2, 1-4). - The Manual D goal: duct system resistance shall match the external static pressure (ESP) produced by the blower package when it delivers the desired Cfm (Section 1-5). Always read blower table footnotes — if…

South Carolina Air Conditioning | 4 questions (5% of exam) Source: ACCA Manual D (3rd ed.)

Key Concepts

• Pressure units. 27.7 inches of water column equals 1.0 pound per square inch; 1.0 IWC = 249 Pa. (Section 1-1)
• Friction rate vs. pressure drop. A pressure drop is the loss between two points (IWC); a friction rate is a pressure drop referenced to 100 feet of duct (IWC/100 Ft). Friction charts and slide rules use 100 feet as the reference distance, so pressure drop must be converted to a friction rate before sizing. (Sections 1-6, A2-2) They are equal only when the run is exactly 100 feet long. (Section A2-2)
• Available static pressure. Component pressure drops are…

Key Concepts

• Throw and draft. Throw is the distance air travels from the duct outlet before it slows to 50 fpm (Modern Refrigeration and Air Conditioning, Sec. 29.2.1, p. 748). Separately, air leaving a supply register at more than 500 fpm causes occupants to feel a draft (Ch. 29; Ch. 30 review). Drafts of 15 fpm to 25 fpm are allowable in a room; below 15 fpm air stagnation results (Sec. 30.1.1).
• Duct dimensions / transitions. When reducing a round or rectangular duct, the taper is approximately 1″ for every 4″ of length. When a duct is being enlarged, the cross-sectional dimension increases 1″ for every 4″ to 7″ of length (Sec. 29.4.4, p. 763).
• **Fire…

Key Concepts

Fire and smoke protection - Fire damper hour ratings must be 75% of the hour rating of the wall, floor, or partition penetrated (Modern Refrigeration and Air Conditioning, 20th ed., Section 29.4.6, p. 767). - Vertical ducts serving two or more floors must be enclosed in a fire partition with fire dampers installed; ducts of less than 20 in² (129 cm²) area do not require a fire damper (Section 29.4.6, p. 767).

Registers, diffusers, grilles - Return grilles are nonadjustable and block about 30% of the air, so the duct cross section is usually enlarged at the grille; the enlargement also slows air movement and reduces noise (Section 29.4.5, pp. 765–766). - Throw = distance primary air…

Key Concepts

• Aspect ratio and metal use. Aspect ratio is the wide side divided by the narrow side; a 24″ × 8″ trunk is 24 ÷ 8 = 3, a 3:1 ratio, which sheet metal contractors call Class 3. A 1:1 ratio (Class 1) gives the smallest perimeter — and the least metal — for a given cross-sectional area (Modern Refrigeration and Air Conditioning, 20th ed., p. 764).
• Transitions. Any change in duct size should be tapered: when reducing, about 1″ for every 4″ of length; when enlarging, increase the cross-sectional dimension 1″ for every 4″ to 7″ of length (p. 763).
• Starting collars. Round duct connects to a rectangular plenum with a starting collar: the…

SC Mechanical Code 2021, Chapter 6 (Duct Systems); ACCA Manual D

Key Concepts

Materials and construction standard. Nonmetallic ducts "shall be constructed with Class 0 or Class 1 duct material and shall comply with UL 181. Fibrous duct construction shall conform to the SMACNA Fibrous Glass Duct Construction Standards or NAIMA Fibrous Glass Duct Construction Standards." (SC Mechanical Code 2021, § 603.5)

Temperature limit. "The air temperature within nonmetallic ducts shall not exceed 250°F (121°C)." This is a maximum, not a design setting. (§ 603.5)

Includes Air Distribution content.

Key Concepts

Ozone and electronic air cleaners - Electronic air cleaners can slightly increase the ozone content of circulated air. For continuous occupancy, ozone should not exceed 0.01 ppm. The 0.1 ppm figure is the maximum level generally considered permissible for an eight-hour exposure — a different case, not a continuous-occupancy limit. (Ch. 28, "Ozone (O₃)," Page 722)

IAQ standards and agencies - ASHRAE Standard 62 is a widely recognized indoor air quality standard, offering equipment and system requirements and minimum ventilation rates. It establishes the IAQ-related standard for the design, construction, startup, operation, and maintenance of ventilation systems in commercial structures. (§28.1, Page 720) - Standard 62.1 ties ventilation rates to the number of…

South Carolina — Air Conditioning Exam

Key Concepts

Ventilation load fundamentals (ACCA Manual N, 5th ed.) - Engineered ventilation systems increase winter heating load and winter humidification load, increase the summer sensible load, and affect the latent cooling load (Manual N, Section 10, Page 87). - Uncontrolled ventilation is outdoor air entering through conventional openings or incidental gaps/cracks (infiltration). Do not assume infiltration satisfies a code requirement, and do not use the code ventilation requirement as the infiltration Cfm input value (Manual N, Section 10-1, Page 87). - T_room is always the design indoor temperature; T_vent equals the outdoor temperature when outdoor air is introduced directly to the space, to the return side of an air handler, or to…

Key Concepts

Exhaust discharge location (SC Mechanical Code 2021, Section 501.3.1). Termination points must meet minimum distances that differ by the type of exhaust:

• Item 1 — explosive or flammable vapors, fumes or dusts: 30 feet from property lines; 10 feet from operable openings into buildings; 6 feet from exterior walls and roofs; 30 feet from combustible walls and operable openings into buildings that are in the direction of the exhaust discharge; 10 feet above adjoining grade.
• Item 2 — other product-conveying outlets: 10 feet from property lines; 3 feet from exterior walls and roofs; 10 feet from operable openings; 10 feet above adjoining grade.
• Item 3 — all environmental air exhaust: 3 feet from property…

Key Concepts

Definitions (Subpart C, §1926.32). A competent person is "one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them" (§1926.32(f)). No degree, years of experience or certificate is part of that definition. Compare qualified (§1926.32(m)) — recognized degree, certificate, professional standing, or extensive knowledge/training/experience — and authorized person (§1926.32(d)). "Shall" is mandatory; "should" is recommended (§1926.32(q), (r)). Employers must make frequent and regular job-site inspections by competent persons they designate (§1926.20(b)(2)).