Lightning Protection Institute Lightning Protection Institute

Designer Inspector

Designer Inspector Series

This series of tests consists of two 2-hour exams to reach the level of Designer Inspector and may only be taken by LPI Professional Members. Testing is not a requirement, however, for membership in the Professional Division of LPI. This program is available to enhance credentials by showing a high level of proficiency in lightning protection.

Exams are given once yearly at our spring Annual Conference. However, an applicant wanting to sit for the exam at alternate times or sites may arrange for the LPI to work through a proctor. The applicant is responsible for finding a proctor (we suggest contacting a local library or college, who often have persons that proctor tests) and making all arrangements with the proctor. A proctor cannot be employed by the applicant’s business or be related to the applicant. Any charges for proctor services are the responsibility of the applicant, and no billing will be handled by the LPI for these services.

The LPI will mail exam(s) marked for the applicant to the proctor. After the proctor oversees the test taking, he/she will return the completed exam(s) to the LPI with a notice certifying his/her monitoring of the examination process. The LPI office will score the exam(s) and notify the applicant of the results in writing.


The fee for each exam is $100, payable prior to the exam(s) being sent to a proctor. *There is a 50% discounted rate on each test if taken at our LPI/ULPA Annual Conference (please mark on your application the Proctor is “Annual Conference” so we can distinguish your application). The exams require 70 percent or more correct for passing. Examinations that are not passed may be retaken at any time by following the above procedures. To retake the test you must complete a new Test Registration Form and pay the fee just as before.

Designer Inspector re-certification fees of $75 will be billed and due on December 31st of each year and includes an update test when lightning protection standards change, approximately every 3 years.


Exams are not open book tests. Applicants may use a regular ruler, an Engineering Scale ruler, an Architectural Scale ruler, and a calculator. Cell phones must be turned off.

All tests and materials not used within 60-days of receipt by the proctor must be returned to the LPI office. Applicants must reapply and pay the full fee if the tests are resent. No refunds will be given for tests in any way, whether completed or not completed.

Study Materials

Study materials for the exams are available for sale through the online store. Copies of the NFPA-780 Standard sell for $76.00. Copies of the LPI-175 Standard can be purchased for $40.00-$55.00 (download or hard copy options available). Hard copy prices include all shipping and handling.

Registration Options

If you wish to take your exam at the LPI Annual Conference you cannot use an online registration form, please use the paper form below.

Sample Questions


Multiple Choice

Short Answer


  1. Connections of roof cable conductor to structural steel used as downleads must be made by connectors with a minimum of 3 square inches of contact area.
  2. Only 1 air terminal must be mounted to a chimney if located within 24 inches of all outside corners.
    In no case, shall 2 downleads be spaced closer together than 100 feet.
  3. Any properly grounded structural steel framing member (beam or column), which is 1/4″ thick, would qualify as a substitute for a main cable conductor.
  4. All metal guy wires for protected chimneys or vents must be connected to the lightning protection system at their top and bottom.

Multiple Choice

6. A 60 foot tall flat roof building is classified as:

Class I structure
Class I modified structure
Class II structure
Class II modified structure

7. Class II solid copper air terminals must be of what minimum diameter?

1/4 inch
3/8 inch
1/2 inch
5/8 inch

8. The minimum weight requirement for Class I copper conductor is…

95 lbs. per 1000′
187 lbs. per 1000′
190 lbs. per 1000′
375 lbs. per 1000′

9. The minimum ground resistance specified in the Standards for a lightning protection system grounding electrode is…

5 ohms
25 ohms
50 ohms
None of the above

10. The material no longer allowed by NFPA for a driven grounding electrode is:

Copperclad steel
Galvanized steel
Solid copper
Stainless steel

Short Answer

11. Services entering a structure fall into 3 categories that specifically require a surge protection device. Name the 3 systems identified by NFPA-780.

12. The type of metal body that must always be considered for bonding is a/an ________ metal body.

13. The minimum total number of air terminals required to protect a flat top mechanical unit measuring 4 feet wide x 10 feet long is ________ .

14. Trees are recommended to have 2 downleads when the trunk exceeds a diameter of ______ feet.