Expansion joints of the slip type shall NOT be inside buildings or for thermal expansion.

• A. False
• B. Not applicable
• C. Only for outdoor use
• D. True

Answer: (D)

Expansion joints that slip rely on a sliding connection to absorb movement. Inside buildings, the environment demands joints that are leak-tight, sealed, and able to maintain performance under regular thermal cycling without shifting, leaking, or gathering debris. A slip-type joint, with its sliding interface, is more prone to leaks, wear, dirt intrusion, and loss of seal as movement occurs, and it typically cannot handle the long-term thermal expansion and contraction experienced in indoor piping. For these reasons, slip-type expansion joints are not placed inside buildings or used to accommodate thermal expansion. Instead, interior applications use joints designed to maintain a reliable seal and withstand repeated cycling, such as properly engineered expansion joints (like bellows or flexible couplings) or expansion loops with appropriate anchoring.