【Cause】Problems that are often overlooked in daily engineering work

【Cause】Problems that are often overlooked in daily engineering work

I am elevator specialist (Ethan Liu). The "issues commonly overlooked in day-to-day engineering" you mentioned are very critical—these are often not isolated technical errors but systematic management oversights, especially at multi-discipline interfaces, in process sequencing, and in late-stage O&M forecasting. Such issues are particularly prominent in complex, operationally demanding projects like hotels; once overlooked, they may at best affect commissioning progress and at worst lead to equipment damage or even safety hazards. Below, drawing on my engineering experience, I outline several typical and easily overlooked issues from the perspective of elevators and associated MEP systems, with reference to standards.

1. "Reserved openings and embedded parts" details for shafts and machine rooms are overlooked

• Phenomenon: Excessive shaft verticality deviation, ring beam spacing not meeting elevator guide rail bracket installation requirements, wrong positions or insufficient dimensions of reserved openings in the machine room, machine room load-bearing beams not constructed per drawings, etc.
• Standard Reference: GB/T 10060-2011 *Code for acceptance of elevator installation* Clause 4.1.1 explicitly requires: "Before elevator installation, the civil engineering works of the machine room, shaft and pit shall comply with the requirements of the design drawings, and their dimensional deviations shall be within the permissible range." Clause 4.1.3 requires: "Permanent lighting shall be provided in the shaft and shall comply with relevant standards."
• Engineering case: In a five-star hotel project, the elevator shaft was designed as a shear wall structure, but during civil construction, ring beam embedded parts were not reserved per the elevator drawings. After the elevator installation contractor entered the site, it was found that the guide rail brackets could not be fixed, requiring extensive post-installed rebar in the shear wall. This not only increased schedule and cost but also, due to insufficient embedment depth, caused slight sway during later elevator operation. Structural strengthening ultimately had to be carried out, resulting in approximately RMB 150,000 in additional expenditure and a 2-week schedule delay.
• Solution: At the civil-to-elevator-installation handover, a joint technical briefing must be conducted, and concealed works acceptance must be strictly implemented. For example, before shaft concrete pouring, the elevator specialist engineer should verify on site the ring beam positions, reserved opening dimensions, pit depth and waterproofing grade.

2. "Interface protocols" between elevators and weak-current intelligent systems are overlooked

• Phenomenon: Fire signals cannot directly trigger elevator homing, elevators do not automatically select floors after access card swiping, the intelligent dispatching algorithm cannot obtain passenger flow data, elevator operation data cannot be uploaded to the energy management platform.
• Standard Reference: GB 50016-2014 *Code for fire protection design of buildings* Clause 7.3.1 requires that "fire elevators shall be available for firefighters in case of fire and shall have linkage control functions." GB 50314-2015 *Standard for design of intelligent building* Clause 11.3.2 requires that "the elevator system should be networked with the building equipment management system to achieve information sharing and linkage control."
• Engineering case: During pre-opening fire acceptance of an international brand hotel, it was found that the homing signal sent from the fire control room could not be received by the elevators. Investigation revealed that the fire alarm system used dry contact signals, while the elevator control system required the RS485 communication protocol, and a protocol converter was missing in between. A gateway had to be urgently procured and installed to pass acceptance, but the opening plan was already affected.
• Solution: In the elevator tender technical specification, all systems requiring linkage and their communication protocols (such as BACnet, Modbus, dry contact, TCP/IP, etc.) must be clearly listed, and the elevator supplier must be required to provide detailed interface schematics and commissioning plans. At the system integration commissioning stage, a dedicated "joint commissioning" schedule should be arranged to ensure correct linkage logic among systems.

3. The "actual operating conditions" of elevator selection and hotel operational needs are overlooked

• Phenomenon: Serious queuing of guest room elevators during morning peak and of banquet hall elevators at meeting dismissal times; freight elevator dimensions cannot accommodate large linen carts or food service carts; fire elevators do not account for shaft waterproofing or pit drainage.
• Standard Reference: GB 7588-2003 *Safety rules for the construction and installation of electric lifts* and its Amendment No. 1 specify car dimensions, rated load, door opening width, etc., but do not mandate selection calculations. However, GB/T 24476-2009 *Safety rules for the construction and installation of lifts, escalators and moving walks* recommends passenger flow analysis based on building type.
• Engineering case: In a convention-type hotel, the banquet hall was located on the second floor, and only two 1.6-ton passenger elevators were configured per conventional hotel standards. After opening, it was found that when large banquets ended, more than 400 people needed to be evacuated through these two elevators, with an average waiting time exceeding 8 minutes, causing numerous complaints. An additional escalator had to be added later to resolve the issue.
• Solution: For large hotels, professional passenger flow analysis must be conducted (e.g., using elevator traffic calculation software) to determine the number, speed, load and group control strategy of elevators according to the hotel's functional zones (guest rooms, dining, meetings, fitness, etc.). Meanwhile, freight elevator dimensions must match the sizes of linen carts, garbage carts and kitchen food service carts in the back-of-house area, with sufficient door opening width reserved (at least 1.2 m).

4. "Environmental control" of elevator pits and machine rooms is overlooked

• Phenomenon: Water accumulation in the pit causes corrosion of buffers and governor tensioning devices; excessive machine room temperature causes frequent faults or protective shutdowns of electronic components such as VFDs and PLCs in control cabinets.
• Standard Reference: GB 10060-2011 Clause 4.1.4 requires: "The ambient temperature of the machine room shall be maintained between 5 and 40℃." Clause 4.1.5 requires: "The shaft and pit shall be waterproof and moisture-proof, and drainage facilities shall be provided."
• Engineering case: In a southern coastal hotel, the elevator pit was not equipped with automatic drainage pumps. During the rainy season, groundwater seepage caused 10 cm of water accumulation in the pit, and the governor tensioning pulley rusted and seized. The elevator trapped passengers due to false operation of the safety gear; maintenance required pumping water and replacing corroded components, taking 2 days.
• Solution: During the construction stage, it must be ensured that the pit waterproofing grade meets the design requirements (at least Grade 2 waterproofing), and automatic submersible pumps with alarm functions shall be provided. The machine room should be equipped with independent air conditioning or ventilation systems to ensure the temperature remains stable at 25℃±5℃ year-round. It is recommended to install temperature and humidity monitoring devices in the machine room and connect them to the building automation system for remote monitoring.

5. The "commissioning and running-in" after elevator installation is overlooked

• Phenomenon: The elevator runs with jerkiness, poor leveling accuracy, loud door opening/closing noise, and vibration caused by uneven wire rope tension.
• Standard Reference: Chapter 5 "Installation Acceptance" of GB 10060-2011 specifies test requirements for elevator running speed, leveling accuracy, noise values, etc., such as "passenger elevators shall start, brake and run smoothly without obvious impact."
• Engineering Case: In an express hotel project, the elevator passed acceptance after only 2 days of operation following installation. After entering service, frequent door jamming and car vibration occurred. Investigation showed that the door operator drive parameters had not been finely adjusted according to door panel weight, and the guide rail joints had not undergone secondary fine adjustment. It ultimately took 3 days of re-commissioning to resolve the problem.
• Solution: Strictly follow the standard requirements and conduct no fewer than 1,000 fault-free operation tests (i.e., "running-in"). Before formal handover, at least 7 days of full-load simulated operation (e.g., simulating morning peak passenger flow) should be carried out, and all faults and abnormalities should be recorded and rectified one by one.

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