Dust And Particles; Air Quality; Corrosion - Cisco Catalyst 9200 Series Hardware Installation Manual

Preparing for Installation

Dust and Particles

Fans cool power supplies and system components by drawing in room-temperature air and exhausting heated
air out through various openings in the chassis. However, fans also ingest dust and other particles, causing
contaminant buildup in the system and increased internal chassis temperature. A clean operating environment
can greatly reduce the negative effects of dust and other particles, which act as insulators and interfere with
the mechanical components in the system. The standards listed below provide guidelines for acceptable
working environments and acceptable levels of suspended particulate matter:
• National Electrical Manufacturers Association (NEMA) Type 1
• International Electrotechnical Commission (IEC) IP-20

Air Quality

Dust is everywhere and often invisible to the naked eye. It consists of fine particles in the air that originate
from various sources, such as soil dust lifted by weather, from volcanic eruptions, or pollution. Dust at an
installation site may contain small amounts of textile, paper fibers, or minerals from outdoor soil. It may also
contain natural contaminants, such as chlorine from the marine environment and industrial contaminants such
as sulfur. Ionized dust and debris are dangerous and get attracted to electronic equipment.
The accumulation of dust and debris on electronic equipment has the following adverse effects:
• It increases the operating temperature of the equipment. According to the Arrhenius effect, an increase
• The moisture and corrosive elements that are present in the dust can corrode the electronic or mechanical
These adverse effects are further accelerated by the presence of fans in the data networking equipment that
ingest dust and other particles into the equipment. Higher the volume of air that is generated by the fans for
cooling, the higher the quantity of dust and particulates that get deposited and trapped inside the equipment.
Remove or minimize the presence of dust and particulates at the installation site by following the guidelines
mentioned in ANSI 71-04-2013 regulations.
Note

Corrosion

Corrosion is a chemical reaction that occurs between electronic components and gases which results in metal
deterioration. Corrosion attacks edge connectors, pin connectors, IC plug-in sockets, wirewraps, and all other
metal components. Depending on the type and concentration level of the corrosive gases, performance
degradation of the components occurs either rapidly or over a period of time. It also leads to blocked currents,
brittle connection points, and overheated electrical systems. Corrosion by-products form insulating layers on
circuits and causes electronic failure, short circuits, pitting, and metal loss.
A type of corrosion known as creep corrosion, that primarily affects PCBA (Printed Circuit Board Assembly)
occurs when the PCBA is subjected to a harsh, and sulfur-rich (hydrogen sulfide) end-use environment over
a prolonged period of time. The corrosion begins on certain exposed metals, such as copper and silver, and
in the operating temperature leads to a decrease in reliability and life of the equipment.
components and cause premature board failure.
In addition to the guidelines mentioned in ANSI 71-04-2013 regulations, follow all applicable guidelines
as per site conditions to remove or minimize other contaminants.
Cisco Catalyst 9200 Series Switches Hardware Installation Guide
Dust and Particles
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