Did you ever wonder whether those flimsy-looking balusters on Colonial staircases — sometimes called "candlestick" balusters — are strong enough to keep someone from falling through them? And more important, whether they're strong enough to comply with the building codes — some of which are quite stringent when it comes to stairs and guardrails? The December '94 Practical Engineering column looked at BOCA code requirements for attaching railing posts. In this article, which is an extension of the same topic, we'll look at the strength of balusters, which by code must meet the criteria for a guardrail "infill." BOCA section 1615.8.2.1 requires that balusters "be designed and constructed for a horizontal concentrated load of 200 pounds applied on a 1-square-foot area at