Argonne National Laboratory seeks a time-and-materials purchasing agreement for on-call HVAC repair, maintenance, and emergency response services at its SGP campus/Argonne site. The contractor must provide qualified labor, supervision, materials, tools, equipment, replacement parts, and technical support to inspect, troubleshoot, service, maintain, repair, and restore HVAC systems and components as needed. Work includes routine and urgent service plus after-hours, weekend, and holiday emergency response to keep HVAC systems safe, reliable, and operational for facility operations, occupant comfort, equipment protection, and mission continuity. Bidders must review and accept applicable Argonne terms, SOW, price schedule, and high-risk supplemental conditions, and provide required documentation such as a signed RFQ page, completed price schedule, representations/certifications, Service Contract Labor Standards certification, Job Safety Analysis, and Certificate of Insurance. No on-site work may begin until the contractor receives a Notice to Proceed from the Argonne Procurement Representative.