Controlled atmosphere stores to 5,000 MT, built to hold gas.

A controlled atmosphere store keeps fruit at low temperature with oxygen held at 1 to 3 per cent and carbon dioxide at 1 to 5 per cent, for months. The refrigeration plant, nitrogen generator and CO2 scrubber set the atmosphere; the building keeps it. A chamber that leaks costs energy every hour it runs and shortens the storage life of everything inside it.

What we have built

Two 5,000 MT stores: for Valley Fresh at SIDCO Industrial Area, Lassipora, Pulwama, and for Suroop Fresh at village Lahe, Shahapur, Thane. Both were delivered as civil, insulation, electrical and refrigeration on one contract. At Lassipora the firm also built a 60,000 sq ft CA store with packing and grading building for Fruit Master Agro. At SIDCO Electronics Complex, Rangreth, Srinagar, a 65,000 sq ft CA store and pack house with external development for FIL Industries. And at HSIIDC Rai, Sonipat, the 1,25,000 sq ft CA store with grading and packing hall for CONCOR, the largest cold chain build in the portfolio by area. At Bathinda, a CA store for Malwa Fresh Food.

Under construction: a pack house with sorting and grading unit and CA storage infrastructure for the State Agriculture Marketing Board, Uttarakhand, at Arakot, Uttarkashi. Renovated or expanded: HPMC's CA stores at Jarol Tikkar and Gumma, and the post-harvest infrastructure at Rohru. Maintained: FHEL's 12,000 MT facility at Rai and HPMC's stores at four locations.

What decides whether it works

Gas-tightness. India's NHB and NCCD standards reference ISO 6949:1988(E) Type-2 for CA chambers. Whether a chamber meets it is decided by panel joints, the continuity of the vapour barrier, the door gaskets and every cable and pipe penetration, all of which are the builder's work. Why gas-tightness is a civil problem explains what to specify.

Chamber sizing and utilisation

NHB norms permit chambers from 50 to 250 MT, and the chamber plan decides how the store earns. Smaller chambers let a promoter open one at a time as fruit comes in, hold different lots at different regimes, and let space by the chamber to FPOs and traders. A 5,000 MT store planned as one large volume is cheaper to build and harder to keep full. We work the chamber plan with the promoter before the structural design starts.