(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

Ducted air conditioning systems are easier to access and maintain than ductless systems because there’s a single outdoor unit and a single indoor air handler. Regular filter changes are required, but frequency depends on local conditions. The ducts themselves do not require cleaning under ordinary circumstances.

Ductless HVAC
On the other hand, ductless air conditioning systems, also known as “split systems,” are flexible to install and efficient to operate. They include outdoor heat pumps that deliver conditioned refrigerant to indoor air handlers called fan coils, or blowers.

MEP Phase – Insitebuilders

The coils in the air handlers are cooled or heated by refrigerant supplied from the heat pumps. A circular fan blows room air over the coils to condition the space. The temperature of the coils and fan speeds are regulated by programmable controllers.

MEP Phase – Insitebuilders

Individual air handlers make it possible to heat or cool the spaces separately. This reduces energy demand and increases operational efficiency because the units are regulated independently.

MEP Phase – Insitebuilders

Control wiring as well as supply, return, and condensation tubing are installed as a bundled line-set within the framing. The line-sets are placed before interior finishes are completed. The distance from the outdoor unit to the indoor air handler is limited by the manufacturer and system specifications.

MEP Phase – Insitebuilders

Room layout and the location of the blowers must be carefully considered to minimize draft and stagnant pockets of air.

MEP Phase – Insitebuilders

A dryer cycle dehumidifies indoor air to improve room comfort. This reduces the need for conditioned air in a well insulated building.

In areas with high humidity, condensation must be carefully controlled to prevent damage and mold. A pan captures condensation below the coil and drains the moisture through flexible tubing to an outside sump.

MEP Phase – Insitebuilders

Direct ventilation is also necessary to reduce humidity and heating and cooling loads from point sources like bathrooms, appliances, kitchens, and high ceilings.

Power to the fans and control circuitry are supported by electrical wiring installed during the next phase of the construction.

.

.

 (To be continued…)

—————————

The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

Heating and ventilation systems are required by all local building codes because of health and safety concerns. Air conditioning is a relatively recent innovation and not required by code, though it is rarely omitted in hot or humid climates.

Ducted HVAC in a split system
Ducted HVAC is more expensive to install and operate but provides a more evenly distributed interior temperature. It is a two part system. An air handler is located in a closet inside the interior space. It contains a circular fan that draws air through a filter and over coils that contain heated or cooled “refrigerant.”

MEP Phase – Insitebuilders

An evaporator is located outside of the building. It houses a reversible compressor or heat pump that regulates the temperature of the refrigerant in the coils (See more about heat pumps here).

MEP Phase – Insitebuilders

The fan in the air handler blows air over the coils and through sheet metal or foil ducts to registers in each room. Dampers and mixing boxes in the ductwork direct air flow according to zones controlled by a central thermostat.

MEP Phase – Insitebuilders

Most residential systems do not include return air ducts. Instead, an opening is located near the interior unit so air can be drawn back into the air handler to repeat the cycle. The result can be quieter and more energy efficient.

Ducted versus Ductless
Ducted HVAC requires careful planning prior to construction. The system evolved from central furnaces or fireplaces that distributed heated air through “tunnels” built into the walls of now antiquated structures. The conditioned air was lost through doors, windows, chimneys, and vents. No air was returned to the heat source.

MEP Phase – Insitebuilders

Ductless systems are much simpler. They send the “refrigerant” through copper tubing from an exterior unit to the coils in fan units located in each interior space (See Solar Colwood and next month’s illustrations).

.

 (To be continued…)

—————————

The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

The plumbing works as a system. Hot and cold water supplies are delivered through pressurized lines to the plumbing fixtures and unpressurized drains remove the waste to a sewerage disposal system.

MEP Phase – Insitebuilders

These drains rely on gravity and the correct slope to sustain the flow of liquid and solid waste to the sewer main. Vents relieve the negative pressure created by the flow.

Waste disposal includes drains and vent
The size and location of the drains and vents are determined by anticipated loads, site conditions, and the local building code.

MEP Phase – Insitebuilders

Plumbing fixtures are connected to branch and main lines that carry the waste to a sewer main. An onsite septic system is used where offsite sewerage treatment is not available.

MEP Phase – Insitebuilders

The tank above the toilet bowl flushes waste into the drains. A p-trap is built into the porcelain base of the toilet. P-traps are used to block sewer gas from entering the house (More on p-traps)

MEP Phase – Insitebuilders

The drain from a sink is sized according to anticipated use. In most cases, the dishwasher and garbage disposal connect to the drain line from the kitchen sink. Under counter relief valves are used as vents for island sinks.

The connection to the grid
Special permits and meters are required to “hook-up” to water and gas mains. The meters are installed by the plumber and certified by the service provider. The utility companies controls the supply lines with lockable street-side shut off valves.

MEP Phase – Insitebuilders

Emergency shut off valves are required on the customer side of a gas meter in most earthquake regions.

Though permits are required, sewer connections are not normally metered. Instead, a central waste line flows from the building to the sewer main (see Preconstruction). Backflow valves are required to block reverse flow from flooded sewers.

 

 (To be continued…)

—————————

The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders.com

 

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

The supply lines that enter the house are installed to serve the mechanical, electrical, and plumbing (MEP) fixtures shown on the construction drawings.

MEP Phase – Insitebuilders

This includes power and communications cables, gas line, special fluids, and a main water line with hot and cold branch lines to the sinks, water closets, baths, and outside faucets. The work begins with the plumbing rough-in.

PEX supply lines
Soldered copper tubing has been largely replaced by polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC) tubes and fittings. Both of these synthetic plastic polymers are said to have latent environmental problems (see this article at Healthy Building Science).

Based on toxicity studies for water supply lines, flexible cross-linked polyethylene (PEX) tubing has shown to be a sustainable alternative to PVC installations. PEX tubing has gained in popularity because its simple installation makes it far less expensive, easier to maintain, and not as prone to environmental contamination.

MEP Phase – Insitebuilders

The PEX system shown in this example includes hot and cold water supplies in combination with recyclable high density polyethylene (HDPE) waste and vent pipes.

In cold climates, the main water supply runs below the local frost line, up into the building through a slab or insulated floor frame, into an insulated mechanical closet that houses a PEX distribution manifold.

MEP Phase – Insitebuilders
One branch of the water line flows from the manifold to a water heater and then back to the hot side of the manifold. Branch tubing then runs from the hot and cold sides of the manifold to shunt valves for each plumbing fixture.

The PEX tubing is color coded red and blue for hot and cold and is strung through the framing like wiring as a single continuous line. There are no inline joints or spliced connections to fail (see www.pexsupply.com).

MEP Phase – Insitebuilders

Be cautious of gas lines
With an abundance of caution, black iron gas lines are installed from the gas meter to the in-line hot water heater, dryer, and kitchen fixtures in lieu of the less expensive corrugated stainless steel tubing (CSST) normally found in most residential construction.

Building codes govern gas pipe material, size, and wall thickness for all underground service. Note that local codes also dictate the size and location of holes cut into the framing as well as the use of protective plates to prevent accidental punctures.

 

 (To be continued…)

—————————

The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders

 

 

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

Before I begin the posts for the building systems, I’ve been asked to describe how the models for these illustrations were made and what programs I use for construction modeling.

Insitebuilders Tutorial

All of the models in our books were built using an older, simpler, and “free” version of SketchUp v5 or v6 (download here)

Overview of Construction Modeling
A construction model is a builder’s tool and has nothing to do with 2D drafting, estimates, or quantity takeoffs. Instead, the models are “piece-based” and constructed just as they would be in the field. They are virtual simulations.

Here are the three basic steps (and their tools)

  1. Move around the model space to orient yourself (Orbit, Pan, and Zoom
  2. Make the pieces for the assembly (Rectangle, Extrude, and Scale)
  3. Snap the pieces together in the sequence of construction (Move. Rotate, and Copy)

A Tutorial: Build a concrete block wall
If you’re new to SketchUp open a new file and play with the program menus, dialog boxes, and navigation tools to see what they do.

When ready:

Manufacture a block (with these tools):

  1. Drag out an 8,16 rectangle (Rectangle tool)

Insitebuilders Tutorial

  1. Extrude up 8 to form the block (Extrude tool)

Insitebuilders Tutorial

  1. Select and Group as a solid (Group tool)
  2. Name the block (Entity Information)

Insitebuilders Tutorial

Repeat the above steps to make a half block (8,8)

Assemble the wall (with these tools)

  1. Drag out intersecting Chalklines (Tape Measure tool)
  2. Select a corner and snap into place (Move tool)
  3. Select an axis and rotate (Rotate tool)

Insitebuilders Tutorial

Adding detail
It gets a little more complicated if you want to add more detail. For example, to edit the block and add hollow cells to illustrate rebar placement.:

  1. Select the block and right click to Edit Group (or double click)
  2. Use Tape Measure tool with Ctrl to drag out chalk lines
  3. Drag out a Rectangle for the cut out
  4. Extrude the cut out down to form the hollow cell

Insitebuilders Tutorial

Here’s the model if you want to deconstruct it (InsitebuildersTut01.skp)

Tips and Tricks

  1. Store new pieces to a warehouse file for use in future models
  2. Use the older and much simpler SketchUp v5 or v6 (download here)
  3. Stay organized with named Groups in the Outliner
  4. Use Construction Lines like you would use chalk-lines in the field.
  5. Setup Shortcut keys and Preferences as you build your model
  6. See our videos on the Insitebuilders YouTube Channel

Insitebuilders Tutorial

  1. If you get really serious, take a look at Mastering the Art of Construction Modeling.

 

 (To be continued…)

—————————

The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders.com

Part 43: MEP Rough-in Sequence

September 20, 2016

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

Mechanical systems bring the house to life. These include metered services provided by public utilities as well as onsite systems like air handling, waste water treatment, and drainage control.

MEP Phase – Insitebuilders

There are also alternative sources of power, water, and waste disposal that can be privately metered to track consumption. Off grid services include septic systems, well water, on-site drainage, grey water collection, alternative power sources, and LP or methane gas.

Indoor Air Quality
Indoor air quality is an important consideration during the installation of the mechanical systems because the building is sealed and will trap airborne volatile organic compounds (VOC) and other contaminants during the rough-in and finish work.

MEP Phase – Insitebuilders

The systems are installed sequentially to minimize contamination, damage, and rework. This includes the cutting and drilling associated with the concealed plumbing, HVAC equipment, line-sets, and ductwork, and finally the electrical wires, boxes, connections, and fixtures.

Building Systems Work Together
After the cabinets are installed and walls painted, the systems subcontractors return to install their plumbing fixtures, finalize the electrical lighting and connections, and clean and balance the HVAC system.

MEP Phase – Insitebuilders

Important is that the finished systems work together, with ventilation and drainage to remove waste, filtering equipment to condition the intake of air and water, and electrical fixtures balanced on engineered circuits to maximize efficiency.

MEP Phase – Insitebuilders

Note that some builders avoid PVC conduit and piping because of the environmental impacts of their manufacture and disposal, but equal consideration should be given to minimize galvanized, lead, copper, and adhesive materials that raise their own environmental concerns.

 

 (To be continued…)

—————————
The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders.com

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

The objective of the Close-In Phase is to seal the house against the weather so that the mechanical, electrical, and plumbing (MEP) can be installed.

MEP Phase – Insitebuilders

A sustainable shell
The house wrap acts as a barrier against drafts and moisture, while insulated doors and windows are caulked and screwed to securely seal openings and minimize heat transfer.

MEP Phase – Insitebuilders

The trim and siding acts as a hard shell to protect the walls in the same way the metal roofing protects the waterproof membrane. The siding is made from a cement based fiber that is long lasting and durable, reducing maintenance, and increasing the product’s life-cycle.

MEP Phase – Insitebuilders

Metal roofing is manufactured from high recycle content steel, coated at the factory to prevent corrosion, and pre-painted to provide a reflective coating that reduces cooling loads in warmer regions or absorbs heat in colder climates.

MEP Phase – Insitebuilders

The resulting enclosure is long lasting and durable with a service life that will minimize maintenance, repairs, and future replacements.

Now for human comfort
Mechanical, electrical, and plumbing (MEP) systems add comfort to the house by supplying water, removing waste, providing heat, ventilation, cooling, and electrical power. They are installed in the following order:

1. Plumbing

MEP Phase – Insitebuilders

The pipes and fixtures supply water and gas and remove waste from the house. Because this includes large diameter pipes and fittings, the bulk of the plumbing is roughed-in to the framing before the other systems are installed.

2. Mechanical

MEP Phase – Insitebuilders

Heating, ventilating, and air conditioning systems use a combination of air handlers and compressors to distribute conditioned air into the building and vent out moisture and contamination. Indoor air quality depends on the efficiency of the balance and correct capacity of the components of the system.

3. Electrical

MEP Phase – Insitebuilders

Human comfort depends on a well designed electrical installation. This includes dedicated circuits, receptacles, lighting, and controls as well as telecommunication wiring. Because wiring for these devices can be easily damaged, the electrical components are the last to be roughed-in to the framing.

Note that experienced construction managers overlap and carefully coordinate the MEP installations as simultaneous tasks to speed the scheduled completion.

 

 (To be continued…)

—————————

The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders.com