Condensation on outer surfaces of an I.G.U
Insulating glass units are designed to reduce the heat loss through the glazing. However condensation can still occur as follows;
Internal (Room side)
If the glass surface is the coldest surface in a room and the relative humidity is high e.g. kitchen or bathroom then condensation will occur. In addition peripheral condensation may be caused due to heat flow through the spacer of the unit, warm edge spacer bar technology can reduce this.
External (Outside)
With the amount of heat being lost through a sealed unit being significantly reduced, the outside pane can become extremely cold. Under localized climatic conditions this may result in moisture condensing out of the atmosphere onto the outside of the sealed unit.
- Haze when viewed from an oblique angle and under certain lighting conditions, haze, which is an optical phenomenon, may appear on sealed units manufactured with coated glass. The visual effect of haze is similar to dust particles covering the glass surface.
- between finished floor level and 800mm above that level in the case of wall, partitions and windows.
- between finished floor level and 1500mm above that level in doors and in side panels which are within 300mm of either edge of the door.
- Glazing in critical locations should either
- not break or break safely (toughened, laminated or wired glass).
- be small in size - miximum width 250mm and an area not exeeding 0.5m2. Glass used in this case may be annealed but must not be less than 6mm in tickness.
- be permanently protected behind a screen.
For further information refer to BS6262-4 Glazing fro buildings - Part 4: Code of practice for safety related to human impact, and appropriate Building Regulations.
