WASHINGTON – U.S. lawmakers are used to a slew of rules about how to conduct themselves, and now they’re anxiously awaiting edicts of another type: how to behave around the pope.

Pope Francis will visit the nation’s Capitol on Sept. 24 as part of his three-day stop in Washington, becoming the first pontiff to address the Senate and House.

Questions abound. Is it out of line to hug the pope when he enters the House chamber, or shake his hand, or touch him at all? Is applause allowed when he speaks, or perhaps an “amen?”

“I’m told that directives are going to go out about that,” said Patrick Conroy, a Jesuit priest who as U.S. House chaplain coordinates the appearances of guest pastors who give the chamber’s opening prayers.

The worry is understandable. Joint meetings of Congress in the House chamber – including the annual State of the Union address by the president – can be full of ceremony, yet also indecorous.

Perhaps the most notorious moment in recent years was when Rep. Joe Wilson, R-South Carolina, shouted “You lie!” during President Barack Obama’s September 2009 speech to Congress after the president said his health-care plan wouldn’t cover undocumented immigrants.

House Speaker John Boehner, R-Ohio, a Catholic, extended the invitation to Pope Francis to speak at the Capitol. The pontiff also will appear at a White House welcoming ceremony, and he will celebrate Mass at the Catholic basilica in Washington.

Given the need for protocol tips, Conroy met last week with Boehner’s chief of staff, Michael Sommers, and said he was assured that guidance for lawmakers will be sent out soon.

So then, what is proper behavior for a lawmaker? Based on the advice of Catholic church experts and past State Department protocol guidance, here is some advice to lawmakers about the pope’s visit:

Appropriate dress. The rules are basic: Wear dark colors. For women, sleeves should cover the shoulders and elbows, and hems should fall below the knees.

Touching the pope. Is it allowed? No one is supposed to approach him without an invitational gesture. But experts say it’s unlikely he’ll enter the center aisle without reaching out to some lawmakers.

What to do if the pope approaches you? Previous State Department advice suggests that when greeted by the pope, one should either shake his hand, or if you are Catholic and want to do so, kiss the pope’s ring – worn on his right hand.

What to call the pope. This is pretty clear: He should be addressed as “Your Holiness” or “Holy Father.” President George W. Bush was criticized during a visit to the Vatican in 2007 for calling Pope Benedict XVI “sir” several times.

Standing ovations. These are a staple of State of the Union addresses. Still, for the pope’s speech, standing and clapping would be viewed as tacky.