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Damp proofing in construction is a type of moisture control applied to building walls and floors to prevent moisture from passing into the interior spaces. Dampness problems are among the most frequent problems encountered in residences. DPC visible between concrete foundation and brickwork.
Humidity occurs in indoor environments due to building related causes. Porous walls, rising damp, and leaks in the building are determinants for structural dampness due to elevated humidity levels. [4]: 185–187 The construction of the building can also lead to humidity and unwanted moisture in the indoor environment. [15]
In construction, a building or structure is waterproofed with the use of membranes and coatings to protect contents and structural integrity. The waterproofing of the building envelope in construction specifications is listed under 07 - Thermal and Moisture Protection within MasterFormat 2004, by the Construction Specifications Institute, and includes roofing and waterproofing materials.
Plumbing systems also service air distribution/control, and therefore contribute to the mechanical part of MEP. Plumbing for HVAC systems involves the transfer of coolant, pressurized air, water, and occasionally other substances. Ducting for air transfer may also be consider plumbing, but is generally installed by different tradespeople. [11]
The control system can compare the temperature of the outside air vs. return air, or it can compare the enthalpy of the air, as is frequently done in climates where humidity is more of an issue. In both cases, the outside air must be less energetic than the return air for the system to enter the economizer mode.
The most common indoor pollutants monitored in DCV systems are carbon dioxide and humidity. [1] This control strategy is mainly intended to reduce the energy used by heating, ventilation, and air conditioning (HVAC) systems compared to those of buildings that use open-loop controls with constant ventilation rates.
A moisture meter gives a reading of the approximate moisture content of wood. The reading helps in determining whether the wood is suitably dry for its intended purpose. The moisture content reading can also assist in planning a project design that will accommodate future changes in dimension caused by changes in relative humidity.
By comparison, thermal comfort standard ASHRAE 55 requires systems designed to control humidity to maintain a dew point of 16.8 °C (62.2 °F) though no lower humidity limit is established. [44] Water vapor is a lighter gas than other gaseous components of air at the same temperature, so humid air will tend to rise by natural convection. This ...