Water enters the building from the municipal main or a private well, typically passing through a water meter and a main shut-off valve.

• Cold Water Line (CWL): Usually drawn as a solid line (often blue in color CAD) with a specific linetype (e.g., a dash and a single dot).
• Hot Water Line (HWL): Usually drawn as a solid line (often red) with a specific linetype (e.g., a dash and two dots).
• Valves: Gate valves (wheel handle) or Ball valves (lever handle) are strategically placed to isolate sections of the building (e.g., shutting off water to one bathroom without affecting the entire house) for maintenance.
• Water Hammer Arrestors: Small vertical pipes filled with air placed near quick-closing valves (like washing machines) to absorb the shockwave and prevent the pipes from banging.

Unlike supply lines, drainage relies entirely on gravity and air pressure to move waste effectively.

• Waste Lines: Carry "grey water" from sinks, showers, bathtubs, and washing machines.
• Soil Lines: Carry "black water" (containing fecal matter) from toilets and urinals.
• Slope (Grade): The most critical element of drainage design. Horizontal pipes must slope downward toward the sewer. The standard minimum slope is 2% (or 1/4 inch drop per foot of run) to ensure that liquids and solids flow together at a self-cleaning velocity. Too flat, and the solids settle and clog; too steep, and the liquids run past the solids, also causing clogs.
• Traps (P-Trap): Every plumbing fixture must have a U-shaped bend (a trap) located immediately below it. This trap holds a small amount of water (the trap seal), which physically blocks toxic and foul-smelling sewer gases from flowing back up the pipe and into the room.
• Cleanouts (CO): Removable plugs providing access to the inside of the pipe for clearing blockages with an auger (snake). Required at the base of every vertical stack, at changes in direction greater than 45°, and at regular intervals on long horizontal runs.

A drainage system will not function without a ventilation system.

• Vent Stacks: Vertical pipes extending upward and penetrating the roof to open air.
• Function: They equalize the air pressure within the drainage pipes. Without vents, a large slug of water rushing down a pipe (like a toilet flush) creates a vacuum behind it. This vacuum is strong enough to siphon the water right out of the P-traps of nearby sinks, breaking the seal and allowing sewer gas into the building.
• Vent through Roof (VTR): The termination point of the vent stack above the roofline.

Heating, Ventilation, and Air Conditioning (HVAC) plans ensure proper indoor air quality and thermal comfort.

• Ductwork Layout: Indicates the route of supply air (SA) ducts pushing conditioned air to rooms, and return air (RA) ducts pulling stale air back to the handling unit.
• Diffusers and Grilles: Specifies the size and type of the vent openings where air enters or leaves the space.

Crucial for life safety, detailing automated suppression systems.

• Sprinkler Layouts: Specific patterns of water pipes and sprinkler heads designed to cover distinct fire zones based on building codes.
• Standpipes and Hose Cabinets: Vertical pipes (dry or wet) running up a high-rise building specifically for firefighters to connect hoses to on any floor.

Often separated into two distinct plans to prevent extreme clutter.

• Lighting Layout: Shows ceiling and wall-mounted fixtures (circles, squares, specific symbols for fluorescent troffers vs. LED downlights). The defining feature is the curved, dashed line (a "switch leg" or "control wire") connecting the light fixtures to the specific switch (S) that operates them. A switch with a "3W" subscript indicates a 3-way switch (controlling a light from two different locations, like the top and bottom of stairs).
• Power Layout: Shows the location of electrical receptacles.
  • Duplex Convenience Outlet (CO): The standard wall outlet (often symbolized by a circle with two parallel lines struck through it).
  • Ground Fault Circuit Interrupter (GFCI): A mandatory safety outlet required in wet locations (bathrooms, kitchens, outdoors, garages). It instantly cuts power if it detects a tiny imbalance in current, preventing electrocution.
  • Special Purpose Outlets (SPO): Dedicated, often higher-amperage outlets for major appliances (Air Conditioning Units (ACU), Electric Ranges, Water Heaters).

The "brain" of the electrical design. It is a detailed table listing every single circuit breaker within a specific distribution panel.

• Circuit Number: Odd numbers typically on the left, even on the right.
• Load Description: e.g., "Lighting - 2nd Flr Bedrooms," "SPO - Kitchen Range."
• Load Computation: The calculated power demand in Volt-Amperes (VA) or Watts (W).
• Circuit Breaker Rating (AT/AF): Ampere Trip (the current at which the breaker will automatically trip/shut off to prevent a fire) and Ampere Frame (the physical size of the breaker casing). Typical lighting/outlet circuits use 15A or 20A breakers.
• Wire and Conduit Size: The physical specifications of the conductors based on the breaker size. A 20A breaker typically requires 3.5mm² (AWG #12) THHN copper wire inside a 20mm $\phi$ PVC conduit. The wire must be thick enough to carry the current without melting before the breaker trips.

Moving conditioned air efficiently requires substantial physical space.

• Ductwork Layout: Shows the physical pathways of sheet metal ducts. Dimensions are critical and always given as Width x Depth (e.g., 600x300mm). The duct size generally decreases as it moves further from the air handling unit.
• Supply vs. Return: Solid lines typically indicate Supply Air (SA) ducts pushing cold air into a room via ceiling Diffusers (marked with an 'X' or arrows pointing out). Dashed or differently patterned lines indicate Return Air (RA) ducts pulling warm air back via Grilles (marked with parallel lines or arrows pointing in).
• Equipment: Locates massive machinery like Air Handling Units (AHU), Fan Coil Units (FCU), Chillers, and Exhaust Fans (EF).

The layout of the automatic fire sprinkler network.

• Piping Grid: Shows the main supply pipes (mains) and smaller branch lines feeding the sprinkler heads.
• Sprinkler Heads:
  • Upright Head: Sprays water upward against a deflector to rain down broadly. Used in exposed ceiling structures (like warehouses or parking garages) where the pipe is visible.
  • Pendent Head: Sprays water directly downward. Used in finished rooms with drop ceilings (ACT or gypsum board), where the pipe is hidden above and only the small head protrudes through the ceiling.