The Invasion of Periodical Cicadas

THE INVASION OF PERIODICAL CICADAS

ISSUE:

Affect of Cicada insects on performance of mechanical equipment.

BACKGROUND:

The largest-ever presence of an insect that appears in swarms across large areas of the

United States in 17-year intervals is expected in 2004. Cicadas can overwhelm cooling

towers, evaporative condensers, air-cooled chillers and air-handling units. When

periodical cicadas emerge, their population density is enormous and can exceed 1

million per acre. If a facility is in a brood-infested region and the cooling towers,

evaporative condensers and air-handling units are in or near naturally forested areas, or

are surrounded by trees, these systems would be vulnerable. The insects can be

sucked into the equipment. Units located on rooftops and away from trees or, in the

middle of a paved area are less likely to encounter cicada related problems than those

that are near the ground or surrounded by trees or woody plants.

RECOMMENDATIONS:

1. First, determine if your facility is in an affected region. If you had a problem the

last time, they emerged and there has been little construction or disruption to the

soil or forested areas around your operation, then you are likely to have trouble

again.

2. Research alternatives: Water filtration for cooling towers and air intake filtration

are two good options. These will also help in protecting chillers and heat

exchangers.

3. Air intake filtration systems that mount to the outside of the cooling tower or other

intake openings would filter the air at the point of entry into the system. Do not

use window screens; roll filter media or meshed screens to cover intakes. These

materials can drastically increase static pressure, increase energy cost and

impede cooling efficiency. The intake filtration should provide less than 0.1 in.

w.g. drop in static pressure. Only air intake filtration specifically designed for use

on cooling towers, air-cooled chillers and evaporative condensers should be

used.

REFERENCE: ASHRAE weekly Newsletter, February 12, 2004, article on `The

Invasion of Periodical Cicadas'.

FOR ADDITIONAL INFORMATION: Contact Satish Sehgal at 202-565-5032, Facilities

Quality Service (181A).

19 Feb 2004

FM-181A-DA-118

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