Additional design information necessary to allow large web penetrations to be incorporated into simply-supported bare steel and composite beams is presented in the full booklet. Large penetrations are often made in the steel web of composite beams for the passage of horizontal building services, allowing the plenum height to be reduced when using economical, standard UB and WB steel sections. However, large penetrations weaken a composite beam locally and reduce its overall flexural stiffness, and therefore their effect must be considered in design. Neither the Steel Structures Standard AS 4100 nor the Composite Beam Standard AS 2327.1 contains design provisions for large web penetrations. The rules provided in the booklet for designing bare steel beams with large penetrations are compatible with AS 4100. For the composite state, the rules are compatible with AS 2327.1, and have been proposed as an acceptable method of design to be referred to in Amendment No. 1 of this Standard expected to be published this year. Extract from OneSteel Design of Simply Supported Composite Beams with Large Web Penetrations, Design Book DB 1.3 Ed 2.0. Click here to view website.