An evaluation of scaffold safety at construction sites

PROBLEM: This study evaluated common scaffold safety practices in construction. METHOD: A 150-point checklist was used to evaluate supported scaffold safety practices at 113 scaffolds in nine areas of the eastern United States. RESULTS: Thirty-six scaffolds (31.9%) were either in danger of collapse or missing planking, guardrails, or adequate access. There was a strong statistical correlation between structural flaws and fall protection hazards, and between proper scaffold safety practice and (a) competent persons with scaffold safety training, (b) use of separate scaffold erection contractors, and (c) scaffolds that were not simple frame types. A slightly weaker correlation was found with union status of the scaffold erector, and no correlation was found with geography, site size, number of scaffold users, and trade working on the scaffold. DISCUSSION: Recommendations are made for safer scaffold practice, including a simple four-factor scaffold inspection method. IMPACT ON INDUSTRY: Implementation of the four-factor method could result in a cost-effective way to identify unsafe scaffolds.     

Economic considerations for wastewater upgrading alternatives: an Israeli test case

Sewage effluent for land application is becoming an increasingly important source of irrigation water in many semi-arid regions of the world. Two main approaches to the use of sanitation to upgrade effluent for reuse in agriculture were analyzed: (i) sanitizing to the level required for each crop; or (ii) upgrading all effluent to the sanitary level mandated for unrestricted irrigation (<10 fecal coli/100mL). The first approach was authorized by the Israeli health authorities, who consider irrigation with secondary effluent to be complementary to the treatment process. The other approach was conceived mainly by the agricultural and environmental establishments, which debited the additional financial burden to the urban sector and/or the 'general public'. We show that upgrading all effluents in Israel to 'unrestricted irrigation quality' would cost $69 million each year for upgrading alone, in addition to the costs of treatment to the sanitary level required for each individual crop and of observing all the necessary additional precautions and boundaries. This difference in cost stems from the fact that most effluent is used for the irrigation of non-edible crops, for which partial pathogen removal is sufficient. Thus, upgrading to the sanitary level required by the most sensitive crops would be rather wasteful.