IntroductionLife cycle analysis (LCA) is an assessment method used to assess the environmental impacts of technologies from "cradle to grave" and can be carried out on both products and processes (Huntzinger & Eatmon, 2008). The objective of this report is to critically evaluate some published studies on product life cycle analysis. The product selected for this report is cement and here are the selected published studies that need to be critically evaluated: A Life Cycle Assessment of Portland Cement Manufacturing: Comparing the Traditional Process with Alternative Technologies (2008) Deborah N. Hintzinger, Thomas D. EatmonImplementation of best available techniques in cement manufacturing: a life cycle assessment study (2012)Cesar Valderrama, Ricard Granados, Jose Luis Cortina, Carles M Gasol, Manel GuillemEvaluation of studiesIn order to evaluate the studies, the The most obvious main objective must be to ensure that the life cycle assessment conforms to the standard it adheres to and refers to. The two studies refer to the same standard (ISO 14044) which makes it possible to compare and evaluate each study by lending to the critical evaluation of each. Each effective LCA will involve the following:1. Objective of phases and definition of scope2. Inventory analysis3. Impact analysis4. And interpenetration of resultsProduct and process LCAs should use the same functional unit and equivalent methodological considerations such as performance, system boundaries, data quality, allocation procedures, decision rules and evaluation of impact. It should also be noted that any differences between systems/products or processes relating to any of the above should be identified and reported. The following critically analyzes the two studies...... middle of document ......associated with the use of BAT for the clinker manufacturing process. Evaluating environmental performance and taking into account the LCA methodology proves to be an appropriate process. LCA offers a wide range of improvements through the installation of BAT techniques and this is highlighted in the damage assessment and comparison with those of older production lines. At the conclusion of the critical review of these studies, each report complies with the relevant ISO standard. standards. Despite the acceptance of some minor details and the limitations of the studies, the report appears adequate, in the sense that it is fit for purpose and the terms of the report are quite transparent and consistent. Each of the facts presented and assessments made has a factual basis that actually has great scientific and technical stature. References (Weidema, 1997) (Huntzinger & Eatmon, 2008)