In the domain of Building Services and Maintenance-II, maintenance policies or strategies are foundational for ensuring the efficient operation, longevity, safety, and economic performance of building systems. The maintenance department is typically responsible for managing, organizing, and executing various maintenance activities that help prevent failures, minimize downtime, and optimize resource utilization. These maintenance policies can be classified into different types based on their purpose, timing, and nature of response.

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### Classification of Maintenance Policies/Strategies

The maintenance department generally follows one or more of the following types of maintenance policies/strategies depending on the building type, its usage, equipment installed, and budgetary considerations:

#### 1. Preventive Maintenance (PM):

This is a proactive maintenance strategy designed to reduce the likelihood of equipment failure through regular and scheduled maintenance activities. The primary aim is to prevent faults before they occur. Activities under preventive maintenance include lubrication, cleaning, adjustments, inspections, and part replacements at predefined intervals.

* Example: Regular servicing of HVAC systems, checking and cleaning of air filters every three months, or inspection of fire alarms and extinguishers monthly.

#### 2. Predictive Maintenance (PdM):

Predictive maintenance involves the use of data-driven techniques to assess the condition of equipment and predict when maintenance should be performed. It is condition-based rather than time-based, relying on real-time data from sensors and performance analytics.

* Example: Using vibration analysis, thermal imaging, or ultrasonic tests to detect bearing wear in motors or pumps before they fail.

#### 3. Corrective Maintenance (CM):

Corrective maintenance is the process of correcting faults that have already occurred. It involves identifying and fixing defects after a failure or malfunction. Although not ideal, it is common in scenarios where failure doesn’t lead to severe consequences.

* Example: Fixing a leaking tap, replacing burnt-out light bulbs, or repairing broken door hinges.

#### 4. Emergency Maintenance:

This maintenance strategy is implemented when an unexpected failure occurs that poses a risk to safety, health, or significant disruption to building operations. Emergency maintenance is usually unplanned and must be executed immediately.

* Example: Repairing a burst water pipe, fixing an electrical short circuit, or restoring power supply in a high-occupancy building.

#### 5. Break Down Maintenance (BM):

Breakdown maintenance, also known as reactive maintenance, is a type of corrective maintenance where equipment is repaired only after it fails or breaks down completely. It is generally unscheduled and is performed when the system or component has stopped functioning.

* Example: Replacing a malfunctioning air conditioning compressor after it has stopped working.

#### 6. Condition-Based Maintenance (CBM):

This policy involves monitoring the actual condition of assets to decide what