755 SECTION 685 BRIDGE CLEANING
685.1DESCRIPTION :
The cleaning work shall consist of three phases of cleaning. Phase -One will be a dry, pre - wash cleaning, followed by two -phase water cleaning. All dry, pre -wash cleaning shall be performed prior to any water cleaning, and all water cleaning shall be performed prior t o surface preparation and painting operations. With approval of the Engineer, the Contractor may break this work up into sections or bays.
685.1.1 -Phase One: This phase shall consist of cleaning by dry methods all loose dirt and debris from all areas as noted in the plans. This phase shall be completed prior to any washing operations. Collection may include the use of brooms, brushes, shovels, wheelbarrows, buckets, vacuums, or other suitable means.
685.1.2 -Phase Two: This phase shall consist of washing completely with low pressure plain water the entire bridge deck, curbs, parapets, sidewalks and expansion joints, and any other areas as noted in the plans. All drains shall be thoroughly flushed and shall be free flowing. All debris and trash sh all be removed from the drains. At the nozzle end, the washing equipment shall have a minimum pressure of 3000 PSI and a maximum pressure of 4500 PSI.
685.1.3 -Phase Three: This phase shall consist of washing with a mixture of low pressure water and a solution of a commercial brand soluble salt remover, any areas as noted in the plans. This washing shall be accomplished with a low pressure washer at a minimum pressure of 3000 PSI and a maximum pressure of 4500 PSI, at the nozzle end with the nozzle 4” to 8” from the surface. Remove all surface abnormalities such as rust scale, peeling paint, or blistered paint that would prevent the soluble salt remover from coming into c ontact with the salt contamination. Typically, low pressure water washing is not capable of removing intact coating material. The nozzle type shall be a rotary nozzle. The contractor shall follow the Manufacturer’s recommendations or specifications for m ethod and rate of application of the soluble salt remover. Water shall be from an approved source of drinking water, and the soluble salt remover shall be chosen from West Virginia Division of Highways Approved Source List. The contractor is to place sp ecial emphasis on the top surface of all flanges, connection plates, bearings, and excessively rusty or pitted areas. Any areas of the structure that exhibit mineral deposits of black iron oxide called “black rust” after any abrasive blasting shall be considered contaminated with chlorides and will need an additional washing with the soluble salt remover solution and another abrasive blasting.
685.2 -TESTING OF STRUCTURAL STEEL : The maximum level of chloride contamination shall be 5 micrograms/cm2. Testing method shall be in accordance with The Society for Protective Coatings (SSPC) Technology Guide 15, Section 5.2.5, Latex Sleeve Methodology. In the first 150 sq. ft. of cleaning the contractor is to determine by sufficient testing of the most deteriorated areas (after rust has been removed), the rate of application, nozzle pressure, nozzle distance from surface, and dilution ratio of mixture to achieve the desired level of cleanliness. Thereaf ter, the contractor is to perform test in areas designated by the Engineer to insure that the entire structure has attained the specified level of cleanliness. The Engineer is to verify the degree of cleanliness. The Engineer’s decision shall be final.