I. Case Background and Procurement Requirements Analysis A municipal sanitation department in a coastal city (hereinafter referred to as the 'Procuring Entity') launched a special procurement project for sludge tipper trucks in 2025, planning to purchase three 24 m³ Sinotruk-chassis sludge tipper trucks for sludge transportation from urban wastewater treatment plants to landfills. The total project budget is capped at approximately RMB 1,015,000 (based on publicly available tender information), with an individual unit budget of around RMB 338,000. The Procuring Entity specifically emphasized in its technical specifications that vehicles must be adapted to Quanzhou’s coastal climate—characterized by high temperatures, heavy rainfall, and high humidity—focusing on corrosion resistance of anti-rust coatings, durability of sealing components under hot-humid conditions, and overall load performance during frequent rainy-season operations. Ultimately, Chengli Special Purpose Vehicle Co., Ltd. (hereinafter referred to as 'Chengli') successfully delivered three CLW5250ZWXZ6 sludge tipper trucks—leveraging its mature Sinotruk chassis configuration and upper-structure solutions optimized for hot-humid environments (model number sourced from official MIIT announcement: CLW5250ZWXZ6). These units have been operational in a district of Quanzhou for over six months, receiving positive feedback from the customer. II. How to Draft Technical Specifications: Special Requirements for Hot-Humid Environments When drafting government procurement technical specifications, the Procuring Entity referenced Chengli’s technical parameters and incorporated local climatic characteristics to define the following key requirements: 1. Anti-Rust Coating Requirements Given Quanzhou’s high coastal salt fog concentration, the technical specifications explicitly require a three-layer corrosion-protection system for the truck body and hydraulic piping: hot-dip galvanizing + epoxy zinc-rich primer + polyurethane topcoat. For the CLW5250ZWXZ6 models delivered by Chengli, an additional asphalt-based anti-corrosion coating was applied internally to the cargo box, effectively preventing acidic substances in sludge from corroding metal surfaces. 2. Sealing Component Durability Requirements The technical specifications stipulate that rear door sealing strips must be made of EPDM (ethylene propylene diene monomer) rubber—exhibiting excellent ozone resistance and aging resistance—and must be accompanied by third-party test reports verifying a compression set ≤20% after exposure to 85% relative humidity and 40°C temperature. Chengli’s supplied sealing components were tested under simulated Quanzhou plum-rain season conditions for 120 consecutive hours, showing no leakage or cracking due to aging. 3. High-Load Performance During Rainy Season Considering Quanzhou’s frequent rainfall (average annual rainy days ≈150), the technical specifications require: (a) waterproof breather valves for the hydraulic system; and (b) a minimum body tilt angle of ≥45° to ensure smooth unloading of wet sludge even during rain. Chengli’s delivered vehicles feature Sinotruk’s original hydraulic pump paired with oil- and water-resistant hydraulic tubing. In continuous rainy-day operation tests, these units achieved over 20 unloading cycles per day without hydraulic fluid contamination or lifting mechanism jamming. III. Chengli’s Bid Submission Documentation Checklist In this procurement project, Chengli—as the bidding supplier—provided the following key documents, significantly streamlining the Procuring Entity’s review process: • MIIT Announcement Parameter Sheet: Includes vehicle dimensions, wheelbase, emission standard (China VI), gross vehicle weight rating (GVWR), and other essential data for nationwide registration, annual inspection, and commercial operation eligibility for model CLW5250ZWXZ6. • Corrosion Protection Process Test Report: Third-party certified report verifying hot-dip g