A Study on the Application of Hydraulic Calculations considering the Corrosion Coefficient of Steel Piping for Fire Protection

With the recent enlargement and complication of buildings, damage caused by the incidents of fires breaking out are escalating. Consequently, the use of sprinkler facilities is increasing among water-based fire extinguishing systems. Piping materials used in fire prevention systems include carbon steel (for general or pressure pipeline), CPVC, copper, and stainless-steel. Among these, the steel and CPVC pipes, which are commonly employed in fire prevention, were considered for testing the reliability of the water-based systems. This analysis was performed using the PIPENET software to perform hydraulic calculations in order to examine the flow and pressure at the terminal head when the corrosion coefficient was applied; this coefficient was applied considering the aging of pipes. Assuming a uniform pipe diameter in the steel pipes, the rated flow in the pump installed on the first floor of the basement was reduced by over 10% after 20 years had passed (C value of 90); moreover, the reduction in pressure and flow at its terminal head exceeded 30% and 16.5%, respectively. The results indicate that it is difficult to ensure the reliability of these fire prevention facilities. Furthermore, according to our estimation, considering 30 years had passed (C value of 80), the rated flow of the pump was reduced by over 15%, and the corresponding reduction in pressure and flow at its terminal head exceeded 42% and 24%, respectively.

Research on the Influence of Tension and Compressive Fatigue Load on the Corrosion Coefficient of Parking on the Ground

To ascertain the grounding corrosion coefficient parking on the ground is the key to evaluate the airframe calendar life. The influence of pull and press load on the grounding corrosion coefficient was evaluated in this paper. The main results are as follows. First, the fatigue life always follows the logarithmic normal distribution after pre-corrosion for pull fatigue loading and press fatigue loading. But the scatter of fatigue life for the wing down-panels is reduced with the fatigue life, and the scatter of fatigue life for the wing up-panels is not changed. The second, the coefficient of the wing up-panels test sample is not changed with the increase of the corrosion calendar life. But, the coefficient of the wing down-panels test sample descends with the increase of the corrosion calendar life.

Effect of Phosphorus Slag and Fly Ash on Anti-Corrosion Property of High Belite Cement

Effect of phosphorus slag and fly ash on anti-corrosion property of high belite cement has been researched in the paper. Results show that, the anti-corrosion resistance of high belite cement is obviously higher than mediate heat cement. Admixing one of phosphorus slag and fly ash or both in cement all can improve the corrosion property, but admixing fly ash has more influence. For cement mixed with phosphorus slag and fly ash, effect of the fineness and proportion of phosphorus slag on anti-corrosion coefficient K is not significant.

Experiment Research on the Steel Fiber Reinforced Concrete in the Acid Environment

For the purpose of studying the resistance of steel fiber reinforced concrete against the corrosion of different acid, test compressive strength and flexural strength of the steel fiber reinforced concrete of different volume rate after the corrosion of organic and inorganic acid, and express experiment results with the form of comprehensive corrosion coefficient and the flexural corrosion coefficient in order to reflect the corrosion degree. The results shows that, the organic corrosion has a stronger corrosion effect on the steel fiber reinforced concrete than the inorganic acid under the environment of same PH value. When steel fiber volume rate is 1.5%, the corrosion resistance capacity of the steel fiber reinforced concrete is best.

A Tensile-Load Relaxation Test for Measuring the Stress Enhanced Corrosion Exponent of Ceramics with Open Porosity

A tensile test is proposed for evaluating the stress enhanced corrosion-coefficient of ceramics with open porosity. The analysis of load at fixed grip conditions bases on the assumption that stress corrosion results in a spread of pre-existing generalised damage seen as micro-crack starter due to open porosity. Sub-critical crack extension of microcracks departs from pores and provokes a time dependant diminution of the Young’s modulus, and of the stiffness, of the tested sample. The description derives the number and the size of pre-existing micro-cracks with respect to time. The density of microcrack-nuclei results from the process and belongs to the microstructure, i.e., the number of channels or crack starters, and is considered to remain constant. The rate of diminution of the load is considered, either with respect to the initial one or to a deduced stress intensity factor. Simple relationships yield then an approximate diagram for stress enhanced corrosion. Samples resulting from sintering a mixture of alumina and titania powders were tested under tempered water flow. A stress corrosion exponent, n = 16, near to that of alumina was obtained.