Low Voltage Systems are of High Importance

It is often easy to lump all low voltage systems in a project into one category since they share similar power requirements and characteristics.  However, by lumping them all together, it is easy to forget to include one or more of them in a constructability review.  It is also easy to trivialize their importance, but many low voltage systems are critical to the life-safety features of a building, to efficient energy use, and to the comfort of the building occupants.  

The Impacts:  The primary impacts of forgetting to include a low voltage system in a constructability review are:

1. Lack of a power supply to the controller and/or low voltage equipment.  This may sound like an easy fix, but it may be difficult to extend a spare electrical circuit to a control panel or to individual low voltage components from an existing electrical panel after a building is finished or near complete.
2. Lack of space for the controller or control panel.  One of the most common problems in regards to low voltage systems is not allowing enough wall space for all of the controllers and/or control panels.  Often, electrical rooms are crowded enough with switchgear and electrical panels, leaving little room for the various low voltage panels.  Make sure these are all accounted for on the floor plan and interior elevations so there is room for everyone to fit in the space available
3. Lack of space/coordination of low voltage components.  This third issue is less common, but still worthy of review.  Make sure fire alarm pull stations are in appropriate locations for safe access, make sure fire alarm horn/strobes are not blocked by other equipment and provide adequate room coverage, make sure security sensors and security cameras are not blocked by lighting, equipment, or similar items.

A partial list of low voltage systems is provided below for your reference:

1. Fire Alarm Systems
2. Data/Communication Systems
3. Teleconferencing Equipment and Systems
4. Security Alarm/Detection Systems
5. Security Camera Systems
6. Access Control Systems
7. Lighting Control Systems - Interior and/or Exterior
8. Building Control / Environmental Control Systems
9. Energy Metering Systems
10. Indoor Air Quality Monitoring Systems
11. Irrigation Controller(s)
12. Specialized Equipment Control and Monitoring Systems

Plumbing Walls - Do's and Don'ts

Special accommodations should be made (or at least considered) for all walls that will contain plumbing.  These walls would include the obvious domestic water, sewer and vent lines, and also the less obvious rainwater leaders, gas lines, hydronic lines, condensate lines, and other plumbing.  These accommodations include:

1. Wall/framing thickness - depending on the design requirements and local building codes, the plumbing lines can be larger than you first might assume.  This is especially true of sewer drain and vent lines that are called out as no-hub cast iron or other pipe that has a much larger outside diameter and fitting diameter size than the nominal pipe size called out.  So, first check the line sizes of all plumbing and verify the actual space required for the pipe and fittings.  Then, check the wall framing thickness called out for these plumbing walls and make sure there is enough room.  Six inch studs or a plumbing chase (two parallel framed walls) are often needed to accommodate this plumbing.
2. Structural Supports - When wall-hung sinks and toilets are called out, structural supports (such as "carriers") may be required which take up space.  Make sure these support requirements are spelled out, and there is enough room for the supports, the framing and the plumbing to make it all work.
3. Access Panels - These are often an afterthought, but advanced planning can make sure that all access panels are where they need to be and are located in a place that is aesthetically pleasing.  Access needs include shut-off valves, metering valves, trap priming valves, cleanouts, etc.
4. Concrete Curbs - Less frequent, but still important is to allow for concrete curbs at the base of plumbing walls.  Most often used to limit or contain a water leak and to minimize water-related damage to framing members, concrete curbs can complicate the assembly of plumbing walls.  If these curbs are called out, make sure the curb thickness matches the wall thickness, and that anchor bolts and hold-downs do not interfere with plumbing and other work within the wall.  Also, don't neglect the wall and flooring finishes.  Often, the wall board is intended to extend below the top of curb to allow for wall finishes, but that is not always the case.  Make sure this is planned out for a smooth finished wall to base to floor transition.

The Utilities Above Me

I have mentioned in my "About" page, that many RFI's are repeat RFI's - meaning that they show up again and again on similar projects.  High on the list of repeat RFI's reads an RFI that goes something like this:

In the 2nd floor men's restroom, the finished ceiling is listed as 9'0" above finished floor.  However, the 14" wide flange beam at structural line C and the 16" by 14" supply duct running perpendicular, leave no room for the fire sprinkler line, can lights, or ceiling framing system.  Can we reduce the finished ceiling to 8'6" to accommodate the structure and utilities at this location?

I wish I had a nickel for every time I have written or read an RFI like this one.  

There are a lot of ways to solve this RFI if this issue is discovered early in the design phase, but, most frequently, this issue is not discovered until late in construction when the ceiling framing system is being installed - leaving the project Architect with limited options.

The Cause:  This is a classic case of incomplete coordination of design.  The Architect, Structural Engineer, Mechanical Engineer and Electrical Engineer all have elements of their work that need space above the ceiling, but no one has played "trafffic cop" to make sure it will all fit within the space provided. 

The Best Solution:  So, the trick here is early detection.  This a place where Building Information Modelling (BIM) really shines, but a full BIM model is not really necessary to identify or solve this problem.  All that is required is an overlay of the Structural, Mechanical and Architectural drawings to find out how much above ceiling space is available, and how much is used by structural members, ductwork, etc.  Then, a re-design of those areas that don't fit is required - hopefully well before construction has begun.  The later this issue is discovered and addressed in a project, the more likely it is that lower finished ceilings will result.

Feeling Entitled

Title Reports.  They may seem like an unnecessary expense, but I wholly endorse having a current Title Report on a property before Design work gets underway, and definitely before construction begins.  Here are two good reasons to have a current Title Report:

1.  Utility Easements and setbacks - yes, this is probably the most obvious reason to have a current Title Report.  It is important to determine what portions of a parcel are free of utility easements and setbacks required by the local authorities and utility companies.  You may be surprised at what legacy utility easements exist on the property being developed.  Those easements can greatly restrict your plans for developing a site, but it is better to find that out earlier rather than later.

2.  Verified Property Lines - as incredible as it may sound, I once worked on a school project where only half of the property was actually owned by the school district that was building a small alternative classroom building on it.  The project progressed past the structural phase (steel, in this case), and then came abruptly to a halt when the true property owner filed a trespassing notice.  The project was put on hold for six months while the purchase of the property was worked out between the parties.  In addition to the purchase cost of the property, there were substantial construction delay and re-work costs.  In this instance, a current Title Report would have been cheap insurance compared to these costs.