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Installation of equipment foundation bolts: The saddles of horizontal petrochemical equipment come in fixed-end and sliding-end types. Fixed end: Keeps one end of the device in place, preventing it from slipping or moving as the device operates ； The sliding end is designed to accommodate the corresponding axial displacement that occurs as the device expands due to heat increase or contracts due to temperature decrease in different operating conditions. The fixed end is usually located on the side of the equipment that has large pipes or numerous pipes, or on the side of the feed inlet where the pipes experience significant vibration due to operational factors. The sliding end is placed in a position that is relatively light and has a large coefficient of thermal expansion. Generally, the bolt holes in the fixed-end saddles are circular, while sliding-end saddles usually have oblong holes. During the installation of horizontal equipment, certain technical measures must also be taken to ensure that the sliding-end saddles can move properly as a result of thermal expansion when the temperature rises or thermal contraction when the temperature drops. To enable the sliding end saddle to slide properly, the nuts of the sliding end anchor bolts cannot be tightened directly like those of the fixed end anchor bolts; otherwise, the friction between the saddle base plate and the embedded steel plate in the foundation (sliding plate) becomes too high, restricting sliding and thus preventing it from functioning as intended. Regarding the installation requirements for the foot bolts of the sliding-end saddles, several standards contain similar provisions: In standard 01 GB/T50461-2008, \"Code for Acceptance of Construction Quality of Installation Works for Petrochemical Static Equipment\", clause 4.4.4 stipulates that the foot bolts of horizontal equipment at the sliding end should be located in the middle of the oblong holes in the supports, with any positional deviation being in the direction that compensates for the expansion and contraction caused by temperature changes ； Clean the sliding surface of the bearing and apply lubricant ； After the piping for the equipment is completed, loosen the nut of the foot bolt at the sliding end support to create a gap of 1–3 mm between it and the support plate, then tighten the lock nut. According to 5.3.3 of 02SH/T3542-2007, \"Technical Specifications for the Construction of Petrochemical Static Equipment Installation Projects\", the contact surface of sliding-end supports should be coated with lubricant. The distance between the anchor bolts and the ends of the corresponding oblong holes should meet the expansion requirements. After the process piping is completed, loosen the nut of the sliding end support to leave a gap of 1–3 mm between it and the support plate, and then install a locking nut. According to 4.4.7 of the standard 03HG/T20236-2007, \"Quality Acceptance Standards for the Construction of Chemical Equipment Installation Projects\", the anchor bolts at the sliding ends of horizontal equipment should be located in the middle of the oblong holes in the supports, with their position tilted in the direction of expansion (or contraction) resulting from temperature changes ； Clean the sliding surface of the bearing and apply lubricant ； After the piping for the equipment is completed, loosen the nut of the foundation bolt at the sliding end support to create a gap of 1 mm to 3 mm between it and the support plate, and then tighten the locknut. 4 In accordance with the above **industry standard specifications, the installation of the anchor bolts and nuts for the sliding-end saddles of horizontal equipment shall meet the following requirements: 1. Before lifting the equipment into place, clean the embedded steel plates in the sliding-end foundation and apply lubricant to them ； 2. After the equipment is installed and aligned, tighten the nut at the sliding end first, and then hand over the task to the piping specialists for the installation of the process piping ； 3. After the piping is completed, loosen the first nut of the sliding end saddle, maintain a gap of 1.0–3.0 mm between it and the saddle base plate, and then tighten it with the second nut. In practice, after tightening the nut, loosening it in the opposite direction by one and a half turns usually results in a gap of around 1.0 mm.