North Carolina Energy Code Made Simple

North Carolina Energy Code Made Simple

I recommend memorizing a few things:

  • Chapter 4 – Residential Energy Efficiency
  • Chapter 5 – Commercial Energy Efficiency
  • Use the Table of Contents to look up questions

Define Fenestration, Thermostat Dead Band, Economizers, and COP

Now answer the following question, “What is the difference between the residential and commercial requirements regarding air intake and exhaust damper requirements?”

Hint – look at 403.5 and 502.4.4

Don’t forget

  • Ductwork and pipe insulation requirements
  • Time clock controls
  • Minimum efficiency requirements
  • Sign up for NCCTI’s practice exams

Plumbing Exam Solution

Pythagorean Theorem

For any right triangle, the square of the hypotenuse is equal to the sum of the squares of the other sides.

Run for the door! Cover your ears – there is that “C” word.

Does this bring back school day memories?


C word

Hypotenuse made simple

Forget about Pythagorean Theorem, it’s just simple math.

Calculating C, travel, or hypotenuse is basic math for anybody involved in the building trades.

I have used this formula for sheet metal fabrication. Welders need it as well as Plumbers, Mechanical, and GC Contractors.

Struggling with Plumbing Isometric, Vents and Drains?

Check out NCCTI’s Plumbing Tutorial –

Plumbing Contractor Exam Math 101

Plumbing Math made Simple


Can you tell me why people flunk the Plumbing Contractor Exam by one or two questions?

Plumbing Offset Language

Plumbing Offset Language

Here is a Plumbing Exam Question that pops up from time to time. Answering such questions correctly just might push you over the top.

A sewer is being installed with a 1/8 inch fall for a distance of 100 feet. How much lower will the discharge end over the inlet end?


Here comes that C word!

Let’s covert 1/8 inch to a decimal equivalent  –   1 ÷ 8 = 0.125

0.125 x 100 = 12.5 feet lower or for every 8 – 1/8s  the pipe drops a foot so 100 divided by 8 = 12.5 feet

Pretty simple, How about – if the set = 12.5 and the run = 100, what would the travel equal?

Let’s word this question differently. A sewer installed with a 1/8 inch per foot slope and falls 12.5 feet. How long is the sewer pipe?

Calculate the length of pipe

C – Travel – Hypotenuse

Please send me your answers. I will post the solution soon.

Heating Group 3 Contractor Exams and Manual Q Questions

Heating Group 3 and ACCA  Manual Q

Now that Manual Q is included on H-3 Class I exams, it would be in your best interest to become familiar with the Appendices of ACCA Manual Q.

First, let’s look at Appendix 7 HVAC Duct Design Symbols.

This section has a full page of HVAC Symbols that have been on past Heating Contractor Exams.  Symbols have been on past exams when Manual Q was not be listed as a reference book. Kind of tricky!

ACCA manuals are written by an engineer for engineers.

Reading and understanding ACCA Manuals is a tough pill to swallow. Unfortunately, it’s part of the reference material on the exams. No sense in whining about the ACCA Manuals, this is their game and we have to play by their rules. As there only going to be a few questions from Q on the H-3 exams, I would not put a whole lot of time studying Manual Q. But I would pay attention some to Section 3 and Section 10. Please understand that any section or part of Manual Q is fare game but our goal is to achieve a passing grade and still have a “life”.

Become familiar with Appendix 1 Equations, Appendix 2 Friction Charts, Appendix 3 Charts and design data, and Appendix 7 HVAC Symbols. Some of the Appendices in Manual Q are similar to Manual D, just make sure you keep in mind that Manual D is residential and Manual Q is commercial.

Manual Q and Elevation and Temperature Corrections

On page 3-6, Manual Q, states that” Elevation and temperature corrections are always required when the elevation exceeds 2,000 ft. Now, turn to Appendix 3, Figure A3-4, and at the bottom of page – notes. “Altitude correction not required below 1,500ft.” Read each exam question carefully! Work on increasing look – up speeds.

General Contractor Area Calculations Made Simple

Area calculations made simple

One of the problem areas for many contractors is the blueprint takeoffs.

Let’s face it; most of the exam questions on the blueprint portion are tricky. By  mastering some basic math and committing some  area and volume formulas to memory is a prerequisite for exam success.

Area of triangle = 1/2 [base(span) x height(rise)]

Simple solution

Simple Solution

Calculating the area of a gable is easy once you know the formula.

NCCTI has the winning formula for your success! Sign up now!

Sizing Fuel Gas Lines

402.4.1 Longest Length Method for the Fuel Gas Code

Plumbing, Heating, and Fuel Gas Contractor Exams contain questions on fuel gas pipe sizing. It would behoove applicants to make sure they are comfortable sizing gas lines using the Fuel Gas Tables and Longest Length Method.


Maximum pipe length must be calculated first.

Add up the maximum gas demand, choose the correct Table that matches the fuel being used, and calculate the maximum pipe length from the point of delivery to the farthest outlet. The next step is to choose the correct row in the Table that is equal to or greater than the calculated length. All pipe system values will be taken from this row.


For Contractor exams, use the Longest Length Method.

For residential and light commercial systems, the Longest Length Method is the preferred method. In reality, this method oversize the gas pipe somewhat and would not be a good choice for a large commercial system. The installation cost would come into play.


NCCTI provides a free online Tutorial that will help the student understand the Longest Length Method.

Free Mechanical Contractor Exam Question

Understanding Contractor Exams 101

Do not bring what you do in real life into the exam! I would argue that a person with no Mechanical Contracting experience would fare better on Heating Contractor Exams than an experienced person.

The Board of Examiners Contractor Exams is based Code books and Code is based on the minimum. What this means, if you are a conscientious contractor, then you are doing more than the minimum. You could build a whole house to code and the house could be a piece of junk.


2009 NC Mechanical Code, Section 307.2.3 Auxiliary and secondary drain systems

Look on page19 and read the last sentence in the first paragraph, “One of the following methods shall be used.” Following this paragraph, you have four options to satisfy this code section. I had a student that was taking the H-3 Heating Exam and was asked a question about this section. Instead of reading the appropriate code section word for word and not adding anything to it, he used his experience.


Let’s say we are installing AC equipment in an attic. We use option No. 2 and install a separate overflow drain that connects to drain pan and discharges to a conspicuous place. A smart installer would install a water level detection device too. Why not have some extra insurance against ceiling damage? It’s just makes good business sense! But, it makes bad exam sense.


Derive your answer from reading the code.

The key to success is to read and understand the Exam Question. Read all of the answers. Pick the correct reference book and look up the question in an efficient manner. It takes practice to hone this skill. NCCTI offers Contractor Practice Exams and subject matter Tutorials to serve the Contractor Community. Why wait, sign up now!

Answer to Free Plumbing Exam Question

Answer to Free Plumbing Exam Question

The column of water is 50 foot high.

50’ x .434 = 21.7 psi

On the Plumbing exam, this question might get turned around.


For example;

What is the height of a container that 65 psi is measured at the bottom of the container?

Head = psi x 2.3
Head = 65 x 2.3
Head = 149.5 feet


Need more help to prepare for the North Carolina Plumbing Contractor Exam?

No problem, just sign up for a Plumbing Contractor Practice Exam or order NCCTI’s Plumbing Tutorial.

Free Plumbing Exam Question

Free Plumbing Contractor Exam Question

First, let’s define head – amount of water pressure in a column between points at different elevations that is expressed in feet.

Why do we care about pressure head? Because it’s on the exam, savvy?

Understanding Water Pressure

Let’s take a look at the following example:

Plumbing Head Description

Cubic feet conversion to psi

Now I will break it down further

psi head calculation

0.434 psi = 1 foot and 2.31 feet = 1.0 psi

What is the pressure loss for a 3/8”water supply pipe that travels 50’ vertically?

I look forward to your comments and will post the answer soon.

Two Free Exam Reference Downloads for General Contractors

For Commercial General Contractors

You can download an Excavation PDF from North Carolina One Call. Usually there is a question on color codes relating to excavation near underground utilities. Please note, this excavation pdf is not allowed in the examination room.

For Residential General Contractors

You can download a free guide for “The Guide to Good Practice for Handling, Installing and Bracing of Metal Plate Connected Wood Trusses” summary sheet. You just might see a question on how to properly store wood truss products on the construction site.

Then click truss handling and bracing on the left hand side.

There is nothing better than some free downloads for contractor reference materials!