Continued from Free Electrical Estimating Help #6

Estimating HVAC in Electrical Estimating

HVAC Equipment Schedule

Next, look to see if you have access to the HVAC equipment schedule to determine what kind of units will be installed.

Some of the different types may be as follows:

1. Split Systems, which would have an air handler and a condensing unit
2. Package units, which connect in one location
3. Gas Packs, which usually take less ampacity
4. Electric units, which would take more ampacity
5. Heat Pumps, which would take the most ampacity
6. Boilers
7. Chillers
8. VAV Valves
9. Air Handlers
10. TWU 11.
11. Ductless Split units

Finding Schedules to help with your estimating

Check for fan schedule

Check for the fan schedule also. This will tell voltage and phase, along with any special wiring needed. Most of this information should be located on the electrical drawings. Look for a Disconnect Schedule like the example below:

A disconnect schedule makes it easy. As shown in the example above, all the information that you need for the estimate, except for the distance, is located in one place.

I like to place the distance in the “Notes” space, which keeps everything in one place. If the engineer does not provide a disconnect schedule, you should create one on your own.

For each run, you need to create an assembly for Sealtight/Liquidtite. Your assembly could resemble the example below:

1. 6’ of Liquid-tight—Size as needed
2. 2-Liquid-tight Connectors—Size as needed
3. 16’ of grounding conductor—Size as needed
4. 16’ x number of current caring conductors.—Size as needed
5. 1-Strap—Size as needed
6. 5-Screws

 

Disconnect Schedules

above shows (3) circuits that fit this assembly of products and they are CU-1, CU-2, and CU-4 You would just multiply the QTY above by (3) for quick results. You could end up with something like the following example:

No matter the size of the project, if you break down the plans in small sizes, it is easy to handle. The next step in the HVAC takeoff would be the feeder portion of the circuit. We will use the same method for the feeder as we did for the Disconnect and liquidtite. Below is a list of items needed for the ¾ runs:

After we add the distance of raceways together, it will just be a matter of multiplying this list x the number of runs, which we have identified as being (3).

As shown in the sample Disconnect Schedule above the distance has been added to the schedule. This length should include any additional raceway that is needed for the up the and down portion of the feed. The next step is to add the 3 lengths of raceway and enter that length in the assembly. Then multiply the material x (3).

The results could look like the following example: This is an easy concept to grasp and it works for all phases of estimating.

The heading of the above material could be labeled: To CU-1-CU-2-CU-3 for identification.

One -Line Diagram

Above is an example of a simple one-line diagram. No matter how large or small, you approach it in the same manner. First, list the gear by name.

1. MD panel
2. Panel A
3. Panel B
4. Panel K
5. 3-Pole Lighting Contactor. Mech held
6. Time clock. Tork #EW201

 Note: We suggest including the disconnects that are not listed on the one line in your Request for Gear Quote.

Provide a panel Schedule and specification sheets when submitting the gear for quotation. The supply house should follow the specifications and items listed for quotation. You need to make notes of the following:

1. Voltage
2. Phase
3. Nema configuration
4. AIC rating
5. Main Breaker of Main Lug
6. Top fed or bottom fed.
7. Surface or flush mounted
8. Special size restrictions
9. Any special gear notes such as:
10. TVSS B. Switching breakers
11. Labeling
12. Special metering
13. Digital read outs
14. Remote monitoring
15. ISO Ground
16. SE Rated
17. Construction
18. Copper or Aluminum bus.
19. Etc.

Send the Gear quote and Lighting Quote out as soon as possible to ensure proper bidding time.

Mounting the gear Take notice to see if special attention is given to the installation of the panels. Note: Check to see if seismic engineering is required. This can be quite expensive. Let’s start by looking at the panel schedule of the MDP.

 We note the following:

1. 120/240/3PH/4W (So this project will be unique since it has a delta service) Hot or wild leg
2. 600 amp
3. Main Breaker
4. N3R (So it will be mounted outside) 05. Surface Mounted
5. SE Rated 07. 30K AIC 08. I Line construction
6. The specifications call for a copper buss.
7. No special mounting needs We will add the mounting products of the panels to the estimate. MDP Mounting hardware
8. 6-1/2” lead anchors (for brick)
9. 6-1/2 Bolts
10. 6-1/2 Fender washers Panel A and B Mounting Hardware
11. 8-3/8” Lag screws
12. 8-3/8” Fender washers Panel K mounting hardware
13. 4-1/2” lag screws
14. 4-1/2” Fender washers

Same way for the time clock and the lighting contactor.

Most estimators will just say mounting hardware.

Miscellaneous allowance of $ ___. We now have the Gear “Request for Quotation” sent out and the panels mounted in place. Installing the raceways to power the gear is next.

 

Note: As shown in the example above, I suggest scaling each feeder and recording the distance on the one line diagram as shown in the example above. As with all estimating, we will break the whole into smaller sections.

We now perform a takeoff of the feeders. Riser to MDP Note: The heights of the risers are 20’.

1. 6-3” Unistrut straps
2. 10’ Unistrut
3. 2-3” Myers Hubs (To enter MDP)
4. 2-3” weather heads
5. 40’- 3” GRS.

(Specifications call for GRS outside) Next is installing the conductors. Most estimators will decide how much conductor that they will add for termination and use that length. There will be exceptions to the rule and you may need to adjust that length at times. In this example, we are going to use the choice of 10’ for the riser and 15’ from MDP to the panels.

Having pre-determined lengths in your mind will help you not to get bogged down when estimating. You must use a measure that you are comfortable with and not second-guess yourself.

6. 240’-350 THHN
7. 4-rolls of tape-Black-Orange-Blue-white

For a mental vision, this is what is left. 40 MDP to panel A When I first started, I used to draw the feeder that I was working on so I could visualize the parts needed like the following example.

8. 25’ of #8 THHN
9. 75’-#3THHN
10. 2-1/1/4” Plastic Bushings as shown above 41
11. 2-1-1/4” set Screw Connectors
12. 10’-EMT 13. 2-1-1/4” EMT Straps This is what is left. MDP to Panel B 42
13. The distance horizontal was 60’( 60’ of 2” PVC Sch. 40)
14. 2-2” female adaptors
15. 2-2” GRS 90’s
16. 2-2” GRS couplings
17. 4-2” EMT Connectors
18. 2-2” Plastic Bushings
19. 10’-2”EMT. 5’ at each end. Now for the conductors
20. 60’(Horizontal) + 5 x 2’ ( Rise) + 3’x 2 (for the 90)+15’ for terminating=91’
21. 91’ of #6 23. 273-3/0 THHN Panel B to lighting Contractor and Time Clock
22. 2-1” x 3” nipples
23. 8-1” Lock nuts
24. 4-1’ Plastic Bushings
25. 30’ #10 THHN (the lighting circuits call for number 10 THHN, so we will just include the TC also)

MDP to K Below is the new picture. We have 110’ horizontal as shown in the drawing above. 110’ 44

28. The distance horizontal is 110’(110’ of 2-1/2” PVC Sch. 40)
29. 2-2-1/2” female adapters
30. 2-2-1/2” GRS 90’s
31. 2-2-1/2” GRS couplings
32. 4-2-1/2” EMT Connectors
33. 2-2-1/2” Plastic Bushings
34. 10’-2-1/2”EMT (5’ rise at each end) Now for the conductors.
35. 110’ (Horizontal)+5’ x 2’ (Rise) + 3’ x 2( for the 90)+15’ for terminating=141’
36. 141’ of #6
37. 564-3/0 THHN 45 Grounding
38. Grounding electrode conductor to the building steel is 50’ as shown. 50’ of 2/0 bare copper.
39. Connection to building steel (your choice of connection)
40. 30’ of #6 to telephone as shown
41. Connection to full size ground
42. 20’ of 2/0 bare for water line as shown.
43. 2/0 water pipe grounding clamp
44. 34’ of #4 to connect to footing.
45. Connection to full size ground
46. 2-split bolts to connect to steel in footing.
47. 15’ of #6 to ground rod.
48. Connection to full size ground
49. Ground rod
50. Ground rod clamp

One line Breakdown

No matter how you accomplish this task, this is what must take place. You should compile a complete material list of the products that you just took off, minus the notes.

You will need to price each piece of material. This can be accomplished by sending out to a supply house, using pricing sheets, or a variety of methods. Next, you will record a man-hour for each product listed. You will extend both list for a total material cost and total man-hours. It will look like the example below:

Although your method may look completely different, this is the procedure that you must go through to estimate the one line diagram. Note: We have not included the labor to install the gear itself. You may also include special notes on your line items. When you advance, you will use an electrical estimating software such as the Best Bid.

Understanding Man-Hours

Understanding Man-Hours Every proper electrical estimate must include the time that it will take to install all of the material. This is based on calculating the installation time of each item down to the manhour. Therefore, it is important to understand the use of man-hours. So, what is a manhour? The definition of a Man-Hour is: A man-hour, Labor Unit or Person Hour is the amount of work performed by an average worker in one hour. It is used in written “estimates” for estimation of the total amount of uninterrupted labor required to perform a task. A labor unit is a benchmark used by a company or estimator to determine the labor value of an installation. Notice the word benchmark. Man-hours out of a book are just a great starting point. A good estimator will include their own knowledge and working experience along with the level of difficulty that a certain phase of work will take. It would be impossible to relate all the influences that affect labor units, but you as the estimator must consider Job Difficulty, Installation difficulty, and at what percent of the given man-hours is your company able to perform the work.

Most companies that I have estimated for can install work at about 80% of the book’s man hours. This is for standard 1 and 2-story work with 9’ ceilings. Take into consideration such things as ceiling heights and the floors of a building. All of these factors increase the man-hours. My suggested man-hours would increase to 85% for installations over 10 feet and to 110% for installations of 16 to 20 feet. The same factors should be considered for multiple-story buildings.

Examples of Multi-Story building labor additions 1 to 2 floors +0% 3 to 4 floors +2% 5 to 6 floors +3% 7 to 8 floors +5% 9 to 10 floors +7% 10 to 15 floors +15%

This does not include exposed work, block work or poured-in-place concrete. You may never get a block job by using this tip, but it is my experience that it will take at least double the man-hours to install work in block. I suggest 200% of the book.

Exposed work will take an additional 20% so my suggestion for exposed work would be 100%.

Man-hours are one of the most misunderstood areas of the estimate, but they are simple once you understand it. You can arrive at man-hours by using the following formula. Minutes to perform a task divided by (1 Hour or 60 Minutes) = man-hours. Example: 15 minutes / 60 = .25 man-hours .25 man-hours x 60 = 15 minutes 1 man-hours = 1 Electrician working for 1 hour or 2 electricians working for 30 minutes. So, the amount of time it takes to install electrical materials is measured in man-hours.

This makes calculating time when estimating more precise. It is manageable to estimate a project that will last a couple of weeks just by saying that it will take 1 day to do this function and 2 days to do that function, but when estimating projects longer in duration, then it becomes essential to revert back to man-hours. Each piece of material, no matter how big or how small, will have an associated man-hour. This is the time allotted to install the item.

The following is a Labor Breakdown Conversion Chart:

Labor Unit breakdown .05 Man Hour = 3 minutes .10 Man Hour = 6 minutes .15 Man Hour = 9 minutes .20 Man Hour = 12 minutes .25 Man Hour = 15 minutes .30 Man Hour = 18 minutes .35 Man Hour = 21 minutes .40 Man Hour = 24 minutes .45 Man Hour = 27 minutes .50 Man Hour = 30 minutes .55 Man Hour = 33 minutes .60 Man Hour = 36 minutes .65 Man Hour = 39 minutes .70 Man Hour – 42 minutes .75 Man Hour = 45 minutes 1.00 Man Hour = 1 hour 50 Every estimator should select a standard of man-hours, whether published or created from experience. NECA man-hours have been the benchmark of electrical construction for as long as I can remember. Most all estimates are derived from using standardized manhours. Practical Man Hours As stated before, each item will have an associated man-hour. The process will begin by creating your material list, then placing a man hour by each item, then extending the math and total. Next, you would price each item, and extend the math and total. The following is an example:

 

Also, to have a complete estimate, you will also need to place a price by each item as shown in the following example:

As you can see this is a long and tiring process. I can’t tell you how many 20-page estimates I have penciled in just like the examples above. Hour after exhausting hour of looking up man hours and pricing each line item. With electrical estimating software like the Best Bid by 1CEES, this can be created in detail in seconds not hours. Simply entering the QTY of 10 will produce a detailed list of material with pricing and man hours extended.

**Material List**

1. **12′ of EMT**
2. **2** – 1 1/4” EMT Straps

– Remaining: MDP to Panel B – 42

3. Horizontal distance: **60’** (60’ of 2” PVC Sch. 40)
4. **2** – 2” Female Adapters
5. **2** – 2” GRS 90s
6. **2** – 2” GRS Couplings
7. **4** – 2” EMT Connectors
8. **2** – 2” Plastic Bushings
9. **10′ of 2” EMT** (5’ rise at each end)

**For the Conductors**

10. Total length calculation:

– **60’ (Horizontal) + 5’ x 2’ (Rise) + 3’ x 2 (for the 90) + 15’ for terminating = 91’**

11. **91’ of #6 wire**
12. **273’ of 3/0 THHN** (Panel B to lighting contractor and time clock)
13. **2** – 1” x 3” Nipples
14. **8** – 1” Lock Nuts
15. **4** – 1” Plastic Bushings
16. **30’ of #10 THHN** (Lighting circuits require #10 THHN, so we will also include the time clock)

 

**Updated Measurements**

1. **Total horizontal distance: 110’**

– As shown in the revised drawing.

2. Horizontal distance: **110’** (110’ of 2-1/2” PVC Sch. 40)
3. **2** – 2-1/2” Female Adapters
4. **2** – 2-1/2” GRS 90s
5. **2** – 2-1/2” GRS Couplings
6. **4** – 2-1/2” EMT Connectors
7. **2** – 2-1/2” Plastic Bushings
8. **10′ of 2-1/2” EMT** (5’ rise at each end)

**For the Conductors**

9. Total length calculation:

– **110’ (Horizontal) + 5’ x 2’ (Rise) + 3’ x 2 (for the 90) + 15’ for terminating = 141’**

10. **141’ of #6 wire**
11. **564’ of 3/0 THHN**

**Grounding**

1. Grounding electrode conductor to the building steel: **50’** of 2/0 bare copper
2. Connection to building steel (your choice of connection)
3. **30’ of #6** to telephone as indicated
4. Connection to full-size ground
5. **20’ of 2/0 bare** for the water line as shown
6. **2/0 Water Pipe Grounding Clamp**
7. **34’ of #4** to connect to footing
8. Connection to full-size ground
9. **2 Split Bolts** to connect to steel in footing
10. **15’ of #6** to ground rod
11. Connection to full-size ground
12. **Ground Rod**
13. **Ground Rod Clamp**

**One-Line Breakdown**

 

To complete the task, compile a comprehensive material list of the products mentioned above, excluding notes. Each item should be priced, either by contacting a supply house, using pricing sheets, or other methods. Record the man-hours for each listed product and calculate both total material costs and total man-hours.

**Understanding Man-Hours**

 

This electrical estimate must consider the installation time for all materials, calculated in man-hours. A man-hour (Labor Unit or Person Hour) is the amount of work performed by an average worker in one hour. It’s utilized in written estimates to gauge the total uninterrupted labor required for tasks. A labor unit acts as a benchmark for determining labor value during installation.

 

Though book-supplied man-hours are a good starting point, a knowledgeable estimator will factor in personal experience and the difficulty of specific tasks. Consider that most companies can install work at about 80% of book man-hours for standard 1 and 2-story structures with 9’ ceilings. Adjustments should be made according to ceiling heights and building stories, resulting in increased man-hours for more challenging installations.

**Examples of Multi-Story Labor Adjustments:**

– 1 to 2 floors: +0%

– 3 to 4 floors: +2%

– 5 to 6 floors: +3%

– 7 to 8 floors: +5%

– 9 to 10 floors: +7%

– 10 to 15 floors: +15%

Explicitly note that these percentages do not apply to exposed work, block work, or poured-in-place concrete. For such cases, estimate roughly double the man-hours (approximately 200%). Adding 20% for exposed work should result in estimates being around 100%.

 

**Man-Hours Explanation:**

Understanding man-hours can be simplified with this formula:

– Minutes to perform a task / 60 (to convert to hours) = man-hours.

For instance, 15 minutes becomes 0.25 man-hours, or 1 man-hour equals 1 electrician working for 1 hour or 2 electricians working for 30 minutes.

 

This should help you understand electrical estimating. Let us help