Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology (NIST), nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose.

A proposed test method for the evaluation of low-flow shower heads or flow-restrictor-modified shower heads was developed. The test method provides for the measurement of the principal operating characteristics, i.e., pressure-flow rate dependency and the shower spray distribution. The requirements for laboratory instrumentation suitable for application to the apparatus and the procedures for testing were established. A water collection device, "sector rig", was designed and constructed for the measurement of spray distribution patterns. Experiments were conducted with a small number of shower heads to determine the suitability of the proposed test method. The experimental results indicated the applicability of the method for measurement of spray distribution patterns and other conventional hydraulic performance parameters. A proposed test method for evaluation of shower heads was prepared based upon the analysis of the test results.The test method includes the specification of instrumentation, apparatus, procedures, measurements, and data reduction. Key words:plumbing; shower heads; water conservation; water supply devices.iii PREFACE This report is one of a group documenting National Bureau of Standards (NBS) research and analysis efforts in developing water conservation test methods, models for technical and economic analysis, and strategies for implementation and acceptance of practices.