D. McKinnon, ast technology Labs, Inc. (To be ansi/tia-571-B) Telecommunications Telephone Terminal Equipment Environmental Considerations



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3.7.Temperature Stabilization


Temperature stabilization is considered to be achieved when a centrally located component of the equipment under test does not change its temperature by more than 2°C (3.6°F) per hour.

Figure 1 – PBX with Interfaces


4.TECHNICAL REQUIREMENTS

4.1.GENERAL

4.1.1.REGULATORY REQUIREMENTS


Equipment shall comply with applicable U.S. Federal regulations, which include FCC Part 68 (Ref. A4), FCC Part 15 (Ref. A5), and OSHA 1910.95 (audible noise emission in the workplace), and with industry standard safety requirements such as the NEC, Article 800-4 (Ref. A6), and either UL-1459 (Ref. A7) or UL-1950 (Ref. A8), in the presence of or after subjection to all of the environmental conditions described in this document1.

This document is intended to be in conformity with the FCC Part 68 Rules and Regulations, but it is not limited to the scope of those Rules. In the event that FCC Part 68 requirements are more stringent than those contained in this standard, the provisions of FCC Part 68 shall apply.


4.1.2.PERFORMANCE REQUIREMENTS


This document defines physical and electrical conditions that the equipment may be subject to.

Three levels of environmental conditions are described in this document: level A, level B, and level C. Level A conditions occur regularly, level B conditions occur infrequently, and level C conditions occur as the result of a fault in the equipment or a condition external to the equipment, such as a power line fault, earthquake, or improper installation.

All conditions in this standard are considered level A unless otherwise specified.

Equipment should be capable of normal operation in the presence of or after subjection to the level A and level B conditions described in this document. Equipment shall meet the requirements necessary for safety in the presence of or after subjection to the level C conditions described in this document. It is desirable for equipment to withstand level C conditions. Equipment subjected to stresses (such as shipping) which only occur before or during installation, shall meet all the requirements after installation.


4.1.3.INSTRUCTION REQUIREMENTS


For normal operating conditions, equipment shall comply with this standard without the need for special instructions.

For shipping, installation, maintenance, adjustment, or repair, if equipment requires special instructions in order to comply with this standard, any necessary information shall be specified by the manufacturer in the equipment instruction manuals. This is often required for equipment that is ESD sensitive. It is desirable not to need special instructions for shipping, etc.


4.1.4.COMPLIANCE


Equipment complies with this standard if it meets these requirements when manufactured and after a customer premises installation which follows typical, well documented procedures. The equipment is expected to continue to meet these requirements when properly used and maintained.

Although application of this standard is intended for telecommunications user premises equipment, this standard may also be useful in interfacing other equipment to the public telephone network.


4.2.PHYSICAL ENVIRONMENT


WARNING: ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED
WHEN DROPPING OR VIBRATING EQUIPMENT.

4.2.1.IMPACT

4.2.1.1.PROCEDURE


Impact surfaces are chosen such that they are perpendicular to the direction of motion of the unit at the time of impact. Tests shall be performed as follows:

  • Face Drop. The unit is dropped such that the face struck is approximately parallel to the impact surface.

  • Corner Drop. The unit is dropped such that, upon impact, a line from the struck corner to the center of gravity of the packaged equipment is approximately perpendicular to the impact surface.

  • Edgewise Drop. The unit is positioned on a flat surface. One edge of the rest face is supported by a block so that the rest face makes an angle of 20°with the horizontal. The opposite edge is lifted the designated height above the test surface and dropped.

  • Cornerwise Drop. The unit is positioned on a flat test surface. One corner of the rest face is supported by a block so that the rest face makes an angle of 20°with the horizontal. The opposite corner is lifted the designated height above the test surface and dropped.

  • Random Drop. The unit is positioned prior to release to ensure as nearly as possible that for every six drops there is one impact on each of the six major surfaces and that the surface to be struck is approximately parallel to the impact surface.

4.2.1.2.EQUIPMENT PACKAGED FOR SHIPMENT - DROP STRESSES


Impact shall be made onto a concrete surface. If after six or more successive drops a package has sustained visible damage, the equipment under test may be repackaged before the packaged drop tests are resumed.

  1. Packaged weight of 0-20 lb. (0-9 kg): One 30-inch (76 cm) face drop on each face and one 30-inch (76 cm) corner drop on each corner.

  2. Packaged weight of 20-50 lb. (9-23 kg): One 24-inch (61 cm) face drop on each face and one 24-inch (61 cm) corner drop on each corner.

  3. Packaged weight of 50-100 lb. (23-45 kg): One 21-inch (53 cm) face drop on each face and one 21-inch (53 cm) corner drop on each corner.

  4. Packaged weight of 100-200 lb. (45-91 kg): One 18-inch (46 cm) face drop on each designated rest face. one edgewise drop and one cornerwise drop from a height of 18 inches (46 cm) on each edge and corner adjacent to the rest face.

  5. Packaged weight of 200-600 lb. (91-272 kg): One 12-inch (30 cm) face drop on each designated rest face. one edgewise drop and one cornerwise drop from a height of 12 inches (30 cm) on each edge and corner adjacent to the rest face.

  6. Packaged weight of 600-1000 lb. (272-454 kg): One 8-inch (20 cm) face drop on each designated rest face. one edgewise drop and one cornerwise drop from a height of 8 inches (20 cm) on each edge and corner adjacent to the rest face.

  7. Packaged weight of more than 1000 lb. (454 kg): One 6-inch (15 cm) face drop on each designated rest face. one edgewise drop from a height of 6 inches (15 cm) on each edge adjacent to the rest face.

4.2.1.3.EQUIPMENT UNPACKAGED - DROP STRESSES


Impact shall be made onto concrete covered with 0.125-inch (3 mm) asphalt tile or similar surface.

  1. Hand-Held Items. Normally Used at Head Height : Six random drops from a height of 60 inches (152 cm) 2:.

  2. Table (Desk) Top Equipment, 0-5 kilograms: Six random drops from a height of 30 inches (76 cm).

  3. Other Equipment: The equipment is dropped as follows:

  1. Equipment weight of 0-20 lb. (0-9 kg): One 6-inch (152 mm) face drop on each designated rest face, one 3-inch (76 mm) face drop on all other faces and one 3-inch (76 mm) corner drop on each corner.

  2. Equipment weight of 20-50 lb. (9-23 kg): One 4-inch (102 mm) face drop on each designated rest face, one 2-inch (51 mm) face drop on all other faces and one 2-inch (51 mm) corner drop on each corner.

  3. Equipment weight of 50-100 lb. (23-45 kg): One 2-inch (51 mm) face drop on each designated rest face, one edgewise drop and one cornerwise drop from a height of 2 inches (51 mm) on each edge and corner adjacent to the rest face.

  4. Equipment weight of 100-1000 lb. (45-454 kg): One 1-inch (25 mm) face drop on each designated rest face. one edgewise drop and one cornerwise drop from a height of 1 inch (25 mm) on each edge and corner adjacent to the rest face.

  5. Equipment weight over 1000 lb. (454 kg): One 1-inch (25 mm) face drop on each designated rest face. one edgewise drop from a height of 1 inch (25 mm) on each edge adjacent to the rest face.

4.2.1.4.HORIZONTAL TRANSPORTATION SHOCKS


  1. Packaged weight 0-100 lb. (0-45 kg): No requirement; impact shocks are insignificant com-pared to handling shocks.

  2. Packaged weight over 100 lb. (45 kg): One shock pulse applied on each rest face of the package that might be perpendicular to the longitudinal axis (direction of motion) of a trans-porting vehicle. The shock pulse is a half-sine acceleration, 300 m/s2 peak, 20 ms duration.

4.2.2.VIBRATION

4.2.2.1.EQUIPMENT SHIPPED PACKAGED OR UNPACKAGED


The following sinusoidal vibration in simulation of transportation vibration shall be applied to the unit once in each of three orthogonal directions. One frequency sweep shall be at an acceleration level of 5 m/s2 peak, from 5 to 100 Hz and one sweep at an acceleration level of 15 m/s2 peak from 100 to 500 Hz. The 5-to-100-Hz sweep shall be conducted at a sweep rate of 0.1 octave per minute (approximately 45 minutes), and the 100-to-500-Hz sweep shall be conducted at a rate of 0.25 octave per minute (approximately 10 minutes).

4.2.2.2.EARTHQUAKE ENVIRONMENT


The acceleration levels on the customer's premises due to earthquakes are orders of magnitude lower than the peak levels incurred in shipment. However the equipment can be severely damaged due to mechanical resonance or displacement during an earthquake. It is impracticable to develop generalized requirements that cover all equipment or equipment combinations for all possible conditions in any one of the seven seismic activity zones in North America. However, if a manufacturer claims earthquake resistance for one or more seismic activity zones, documentation shall be made available specifying the seismic activity zones for which earthquake resistance is claimed, as well as any additional installation and building considerations upon which the earthquake resistance is contingent.

4.2.3.AIR PRESSURE


Terminal equipment can be expected to encounter steady air pressures ranging from 68 to 106 kPa (3236 m above sea level to 383 m below sea level).

4.2.4.TEMPERATURE AND HUMIDITY

4.2.4.1.AMBIENT CONDITIONS


Ambient conditions (room temperature and humidity) are defined as +21°C (+70°F) and 50% relative humidity. Ambient temperature is measured at a distance of 15 inches (38 cm) in front of the equipment, at half the height of the equipment, after the air temperature has stabilized. When laboratory conditions differ from this ambient, adjustment to the test specifications may be warranted if needed to achieve an equivalent result.

For the storage and cycling conditions, operation shall be verified after the equipment has stabilized at the ambient conditions.


4.2.4.2.STORAGE

4.2.4.2.1.Thermal Soak

Equipment in its non-operational state shall be subjected to storage conditions by soaking it continuously for 6 hours or longer after temperature stabilization at each of the following points:

  1. -40°C (-40°F) and any convenient humidity (the low temperature point).

  2. +66°C (+150°F) at 15% RH (the high temperature point).

  3. +32°C (+90°F) at 90% RH (the high relative humidity point).

After each 6-hour soak, the unit shall be returned to room temperature. It is desirable to soak equipment at the high humidity point for 96 hours.

These storage tests may be combined with the thermal shock tests of 4.2.4.2.2.


4.2.4.2.2.Thermal Shock

Equipment in its non-operational state shall be subjected to three of each the following thermal shocks (six total):

  1. High Temperature to Room Temperature: After reaching temperature stabilization at +66°C (+150°F) and a relative humidity of 9%, the equipment shall be subjected to a sudden change to ambient conditions.

  2. Low Temperature to Room Temperature: After reaching temperature stabilization at -40°C
    (-40°F) and any convenient humidity, the equipment shall be subjected to a sudden change to ambient conditions.

4.2.4.3.CYCLING


Equipment in its non-operational state shall be cycled for three times at any convenient rate through the following temperature and humidity conditions:

  1. 30 minutes at +66°C (+150°F) and 15 percent RH, followed by

  2. 30 minutes at +32°C (+90°F) and 90 percent RH, followed by

  3. 30 minutes at -40°C (-40°F) and any convenient humidity.

4.2.4.4.OPERATING CONDITIONS


The range of temperature and humidity that the equipment is expected to encounter is defined by an area on a psychometric chart that is specified by four corner points. Operation is verified after temperature stabilization for the low-temperature point (Cold), the high relative humidity point (Damp), the high-temperature/high absolute humidity point (Hot), and the high-temperature/low relative humidity point (Dry), as given in the table below based on the intended use of the equipment.

Range of Temperature & Relative Humidity (RH)




Outdoor Use
Conditions

Unheated Use Conditions

Heated Use
Conditions

Environmentally
Controlled
Conditions

Cold

–40 °C (–40 °F)
50% RH

–20°C (–4°F)
50% RH

0°C (32°F)
~50% RH

5°C (41°F)
~50% RH

Damp

32°C (90°F)
90% RH

32°C (90°F)
90% RH

32°C (90°F)
90% RH

27°C (81°F)
90% RH

Hot

60°C (140°F)
19% RH

46°C (115°F)
39% RH

46°C (115°F)
39% RH

40°C (104°F)
43% RH

Dry

60°C (140°F)
10% RH

46°C (115°F)
10% RH

46°C (115°F)
10% RH

40°C (104°F)
10% RH

Table 1 – Range of Temperature & Relative Humidity


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