Condensation/Cleaning

Condensation
Condensation is formed when moisture in the atmosphere changes back to water as it comes into contact with a surface at a temperature below the 'dew point' of the surrounding air.

Water droplets on the surface of the glazing reduce light transmission, and, if they fall, can spoil plants or damage sensitive goods and equipment beneath. Multiwall PC   (i.e. Polygal Anti Fog) sheet has a special one-side coating that inhibits the formation of condensation droplets. The coating lowers the surface tension and the drops form a thin layer of water over the whole surface of the sheet.

When the sheet is correctly installed, this thin, transparent water film runs off the sheet surface into the profile drainage system without falling to the ground and without significantly affecting the light transmission values of the glazing.

Figure 20 shows a typical condensation predication chart showing the relationships between internal and external temperatures, relative humidity and the U-value. The dotted lines on the chart illustrate clearly how glass with a high U-value is more prone to condensation than the Polygal sheet.

Fig. 20

Example:
Inside temperature: 68 F
Outside temperature: 14 F

Condensation will occur on:

1.	Multiwall 25 mm at a humidity content of:	68%
2.	Multiwall 6 mm at a humidity content of:	50%
3.	Glass at a humidity content of:	32%

Cleaning
Periodic cleaning using correct procedures with compatible household cleaners is recommended to prolong service life.

For general cleaning, it is recommended that the following instructions be adhered to.

Fig. 21

Cleaning Agents Which Have Been Found to be Compatible Polygal Sheet
Joy	various
Palmolive Liquid	various
Top Job	various
VM&P grade Naptha	various

Procedure 1 - Small Areas

1. Rinse sheet with lukewarm water.
2. Wash sheet with a solution of mild soap or household detergent and lukewarm water, using a soft cloth or sponge to loosen any dirt and grime.
3. Rinse with cold water and dry with a soft cloth to prevent water spotting.

Procedure 2 - Large Areas

1. Clean surface with a high pressure water and/or steam cleaner.
2. Use of additives to the water should be restricted to those compatible with Polygal sheet.