In some applications, it may be necessary to install a UL-certified system or perform the work to UL standards. To issue a UL certificate, the installing company must be listed by UL for the category of the installation, such as residential, commercial, central station, etc., and must have the requisite knowledge to design, select and install the equipment. To see if you know what it takes to tackle UL-certified installations, take the following quiz.

1. For an opening to be considered inaccessible, it must be more than how many feet above the ground or the roof of an adjoining building?

a. 3

b. 14

c. 18

d. 20

e. None of the above

2. Which of the following is a manhole-size opening?

a. 48 x 2

b. 32 x 3

c. 24 x 4

d. 16 x 7

e. All of the above

3. Surface-run interconnecting wiring from a control to a safe/vault complete shall be in:

a. protected cable.

b. rigid conduit/emt.

c. interrogate/respond type circuit.

d. Any of the above

4. The tamper switch of an intrusion detector shall be connected to the protection circuit.

a. True

b. False

5. What type of accessible wall construction does not require protection for an extent #2?

a. Gypsum block

b. Brick

c. Cinder block

d. Concrete

e. All of the above

6. Inaccessible movable openings need not be protected for an extent #2.

a. True

b. False

7. Accessible walls do not require protection for an extent #3.

a. True

b. False

8. Photoelectric units shall be mounted so that the beam is not less than 18 inches nor more than 36 inches from the floor.

a. True

b. False

9. A safe complete system must activate an alarm if an opening _____ inches in diameter is made in the safe or safe door?

a. 4

b. 6

c. 48

d. 96

e. None of the above

10. A vault complete system must activate an alarm if a manhole-size opening is made in the vault or vault door.

a. True

b. False

11. A motion detector can be used for complete protection of a vault door.

a. True

b. False

12. Ordinary-use alarm contacts may not be used on a complete safe.

a. True

b. False

13. Which UL standard governs the installation and classification of burglar and holdup alarm systems?

a. 365

b. 634

c. 639


What’s Wrong with This?

Wally `Larman installed a burglar alarm system for a jeweler that consisted of a UL vault complete for a monolithic concrete vault. Wally selected a control, sound detection system and communication path that were UL-listed and installed a motion detector in addition to the magnetic contact to provide protection for the vault door. He tested the system and everything worked as planned, but when the UL inspector arrived, he told the customer that there was a violation. Can you see what Wally did wrong and what he must do to correct the problem?

5-Minute Tech Quiz Answers

1. c – According to UL 681 section 3.23, an opening is inaccessible if it is “more than 18 feet (5.5 m) above either the ground or the roof of an adjoining building.”

2. d – A manhole opening must have a clear cross-section area of 96 square inches or more and have the smallest dimension exceeding 6 inches.

3. d

4. a

5. d – Section of 681 states, “Accessible ceiling, floors, and walls constructed of monolithic concrete or pre-cast concrete building panels do not require protection.”

6. a

7. a – Protection of walls, floors and ceilings is only required for extent #1 and extent #2.

8. a

9. a

10. a

11. b – Since an alarm must be generated when a manhole-sized opening is made in the door, a motion detector is not acceptable. If the door has a total thickness of steel equal to or exceeding 1.5 inches, a sound, smoke or heat detector mounted above the door may be used.

12. b – Ordinary use contacts always may be used on a complete safe if mounted on the inside of the safe or on the outside if used with a capacitance alarm unit.

Answer to: What’s Wrong with This?

Wally’s problem is caused by the method he used to completely protect the vault door. Although motion detectors are acceptable for premises and stockroom protection, they are not acceptable for compete vault protection because they detect motion and will not activate when a manhole-size hole is made in the door or vault. Wally can install a heat detector above the door if the door has a total thickness of steel equal to or exceeding 1.5 inches. If the door has a total thickness of steel less than 1.5 inches, Wally can install an electrical lining or use an acceptable detector specifically listed for protection of the vault door. The motion detector is not needed for a UL vault complete certificate and may be removed, but since it does provide additional protection and is already installed, it can remain as supplemental protection.

Correction: The answer to question 5 in the December 2005 quiz (SDM, December 2005, p. 35) was true, not false as was listed. The explanation is correct as written. SDM regrets the error.