Occupational Health and Safety (OSHA) 10-Hour Construction (OSHA 10)

Correct: A plumbing riser diagram is a non-scaled, schematic representation that illustrates the vertical relationship of the plumbing system. It is the primary document used to show how drains, wastes, and vents (DWV) connect and travel through different floor levels, which is critical for verifying that the venting logic is sound and that the new lines integrate correctly with the existing stack.

Incorrect: A plumbing floor plan shows the horizontal layout of pipes on a single floor but does not clearly illustrate the vertical connections between floors. A mechanical site plan focuses on the exterior of the building, showing underground utilities and connections to the public sewer or water main. A plumbing fixture schedule is a list that specifies the manufacturer, model, and requirements for fixtures like sinks or toilets, but it provides no information about the piping layout or vertical integration.

Takeaway: The plumbing riser diagram is the essential schematic for understanding the vertical flow and venting architecture of a multi-story plumbing system.

Correct: A standard water test for a Drainage, Waste, and Vent (DWV) system requires filling the piping to a specific height, often a 10-foot head, and observing the water level at the highest point. If the water level remains constant for the duration of the test (usually 15 minutes), it proves that the system is watertight and all joints are properly sealed.

Incorrect: Pneumatic tests are an alternative method using air pressure rather than water and are not typically performed concurrently. A pressure of 60 psi is associated with potable water supply testing, not gravity-fed drainage systems. Simultaneous fixture flushing is a functional test for flow and venting capacity but does not satisfy the requirements for a static pressure leak test.

Takeaway: The definitive proof of a successful DWV water test is a stable water level at the highest point of the system over the required duration.

Correct: Fixture Unit calculations are the fundamental metric for determining the hydraulic load and required pipe sizing for a building. Using outdated or incorrect DFU values—especially when combined with a conflict of interest and bypassed controls—creates a high risk that the installed plumbing system will be undersized for the actual demand. This leads to a higher probability of backups, leaks, and catastrophic water damage, which directly increases the insurer’s long-term liability and financial exposure.

Incorrect: Focusing on municipal permits is incorrect because the insurer’s primary concern is the physical risk and financial liability of the asset, not the contractor’s administrative compliance. Attributing the bypass of alerts to a lack of training is incorrect because the scenario describes a conflict of interest and intentional manual overrides, which are indicators of a breakdown in internal controls and integrity rather than a simple skill gap. Suggesting that the conflict of interest is mitigated by the final count is incorrect because the ethical and control failure exists independently of the numerical outcome; the integrity of the risk assessment process is fundamentally compromised.

Takeaway: Accurate Fixture Unit calculations are essential for ensuring plumbing systems can handle hydraulic loads, and any manipulation of these values poses a significant risk to system integrity and insurer liability.

Correct: Plumbing codes and safety standards for Reverse Osmosis systems strictly require a physical air gap on the brine discharge line. This air gap ensures that there is a physical break between the potable water system and the wastewater system. Mechanical devices like check valves are prone to failure due to mineral deposits or debris and are not considered a reliable substitute for the fail-safe protection provided by a physical air gap in preventing cross-connection.

Incorrect: Accepting a check valve is incorrect because mechanical backflow preventers can fail and do not meet the code requirement for a physical break in RO systems. A high-loop configuration, while used in some dishwasher applications, does not provide the same level of protection as a true air gap for RO brine lines. An atmospheric vacuum breaker on the supply line protects the supply from back-siphonage but does not address the risk of wastewater backing up through the discharge line into the RO membrane.

Takeaway: A physical air gap is the mandatory standard for Reverse Osmosis discharge to ensure a fail-safe break between potable water and the drainage system.

Correct: In a vent system, horizontal pipes must be graded or sloped back toward the waste pipe. This is critical because moisture from condensation or minor backups must be able to drain away. If the vent pipe is level or sloped incorrectly, water can accumulate in the line, eventually creating a ‘trap’ in the vent itself that blocks the flow of air. Without air flow, the vent cannot protect the fixture trap from siphonage, which is the primary risk identified in the audit scenario.

Incorrect: Positioning a vent terminal below an operable window is a code violation because sewer gases rise and would likely enter the building; terminals must typically be 10 feet away from or at least 2 feet above such openings. Matching vent piping to water supply materials is incorrect because vent systems (DWV) and water supply systems have different pressure ratings and material requirements. Air admittance valves (AAVs) are mechanical devices used in specific situations where traditional venting is difficult; they are not mandatory for every fixture and are often restricted by local codes compared to standard atmospheric venting.

Takeaway: Effective vent systems rely on proper grading of horizontal lines to prevent moisture blockages that would otherwise compromise the air pressure balance and the safety of trap seals.

Correct: To prevent hazardous pressure drops and appliance malfunction, sizing must be based on the total maximum input rating (measured in BTU/hr or CFH) of all equipment. This ensures that even if every appliance is running at full capacity at the same time, the system provides sufficient volume and pressure to meet the demand without starving any individual unit.

Incorrect: Using average consumption rates is a significant safety risk because it fails to account for peak demand periods, which can lead to flame lift-off or incomplete combustion. Sizing based on wall cavity space is a structural convenience that ignores the hydraulic requirements of the gas system. Implementing a uniform pipe size across all branches is technically incorrect as it fails to account for the cumulative load on the main headers versus the individual loads on branch lines, as well as the friction loss associated with pipe length.

Takeaway: Gas piping must be sized to accommodate the maximum potential load of all connected appliances to maintain safe and reliable delivery pressure during peak usage.

Correct: According to standard fuel gas codes (such as NFPA 54 or the International Fuel Gas Code), any gas piping system that has been added to or altered must be pressure tested to ensure it is gastight. A pneumatic test using a calibrated gauge is the only reliable method to verify the structural integrity of the joints and the piping itself before it is pressurized with flammable fuel gas. This is a critical safety control that cannot be bypassed for convenience or emergency status.

Incorrect: Using flexible connectors does not eliminate the requirement for integrity testing and may not be suitable for all pipe sizes or locations. Combustible gas indicators (CGI) and soap-bubble tests are effective for locating leaks in a system already under operating pressure, but they are not substitutes for a pre-service pressure test which uses higher-than-operating pressure to ensure a safety margin. Periodic soap-bubble tests after the fact do not mitigate the immediate risk of a catastrophic failure upon initial re-pressurization.

Takeaway: All gas piping modifications must be verified for integrity through a formal pneumatic pressure test before the system is returned to service.

Correct: The immediate priority in any power tool malfunction is the safety of the operator and the prevention of further damage. Disconnecting the power source and tagging the equipment (Lockout/Tagout) ensures that the tool cannot be accidentally used by another worker, which is a fundamental internal control for site safety and risk management.

Incorrect: Completing the threading cycle is incorrect because it prioritizes project completion over life safety and could lead to a catastrophic tool failure or fire. Increasing oil flow only addresses a potential symptom of heat but does not address the underlying mechanical or electrical fault indicated by smoke. Adjusting settings while the tool is operational is a violation of safety protocols and increases the risk of physical injury or electrical shock.

Takeaway: Immediate isolation of the energy source and formal communication of the tool’s defect are the most critical steps in maintaining site safety and operational integrity.

Correct: In service and repair practice, the most critical functional step when connecting a dishwasher is removing the knockout plug; failure to do so prevents the dishwasher from draining. Additionally, plumbing codes require a high-loop or air gap to prevent wastewater backflow into the dishwasher, and a proper seal at the sink flange (using putty or a gasket) is essential to prevent leaks that could damage the cabinetry.

Incorrect: Option B is incorrect because motor horsepower is a consumer choice rather than a code requirement, and lubricant is not standard for mounting. Option C is incorrect because electrical requirements vary by local code and are not always 20-amp, and flexible accordion-style tailpieces are generally prohibited by code as they trap debris. Option D is incorrect because silicone on the mounting ring is unnecessary and can interfere with future repairs, and disposal impellers are not sharpened by technicians as they rely on centrifugal force and blunt impact.

Takeaway: A successful garbage disposal installation requires verifying the dishwasher knockout plug removal, ensuring proper backflow prevention for the dishwasher, and establishing a watertight sink flange seal.

Correct: The primary risk in an internal audit context is the impact on business continuity and asset protection. A sewage ejector pump failure in a sub-basement housing UPS systems and physical records could lead to flooding, causing catastrophic data loss and operational downtime. The lack of redundancy (locked controller) and compromised hardware (corroded check valves) significantly increases the likelihood of this high-impact event.

Incorrect: While warranty violations, OSHA compliance, and material compatibility are relevant concerns for facility management, they do not represent the most significant risk to the organization’s core mission of data protection and operational continuity. Warranty costs are a financial nuisance compared to data center flooding; OSHA standards for wastewater are secondary to immediate infrastructure risk; and material compatibility is a root cause rather than the primary operational risk itself.

Takeaway: Internal auditors must prioritize facility risks based on their potential to disrupt critical business infrastructure and compromise data integrity or physical assets.