Research About Pollutants Of Exterior Surface Of Buildings And Feasibility Analysis Of Rainwater To Wash The Wall

In recent years, people pay special attention to the pollutants of exterior surface ofbuilding. Because the usual clean of the wall is more expensive, so researching thecharacteristics of the pollutants of the exterior walls and developing other cleaningequipment makes sense. Taking the contaminated surrounding exterior walls exposed tothe air of Xi,an as the main object of research, the author analyse the characteristics ofthe major pollutants on exterior walls and its,causes, the main polluting formation andtheir forming causes, the usual appearing locations of pollutants and their formingcauses. The author also analyse the characteristics of the rainfall about Xi,an and thefeasibility of the rain to wash the exterior wall. At last, the author obtain the followingmain conclusions:(1) Biological pollution deriving from the organic matter and adequate moisture,corrosion pollution caused by corrosion of the iron products, lime pollution derivingfrom the extravasation of lime included in cement, dust pollution deriving from thesurrounding dust are the four main pollutants. Their colors contain orange、light-yellow、balck、green、white、brown.(2) Two major forms of pollution are the flowing marks class (mainly contain10kinds, such as single strip、maculosus) and painted face which are likely to occur9parts(A-I) around the building protruding or recessed parts.(3) Pollution of exterior walls of the building rose fluctuatly over time.0-5yearsbuilding facades are polluted lighter, which are in the accumulation stage of pollutantsand have little relationship with internal and external affecting factors.11-15years is thesoaring times of the pollutions on the building surfaces. Building maintenance in0-15 years determine the pollution appearing on the wall more or less.(4) A major source of pollution about walls of Xi,an is the dust and pulverized coalparticles in winter. Because of the influence of the surrounding environment such as themonsoon climate, the degree of pollution of the building walls are different, thesoutheast wall> northwest wall, east wall> south wall> north wall> West wall.(5) Pollution characteristics about the particle size of dust particle on the verticaldirection are different form materials to materials, the low section of building isessentially higher than the high section. Degree of pollution caused by the roughness ofthe wall material are different: cement wall> paint exterior wall> ceramic wall>marble wall> aluminum plate wall> no glazed brick wall. The design should payattention to the different pollutions and the color of material used in the wall to cover upthe pollutants.(6) The pH rainwater in rainwater pipe is the neutral range, rain turbidity is about5NTU. Analysing the rainfall data of51years during1961-2011, heavy rain andmoderate rain appear every year, so making use of it with rainwater utilization device tocomplete the washing of the street facades.