TECHNICAL 26 · REFERENCE
Glossary: the words that mean different things to a grower, a mill and a forwarder.
Half the confusion in this trade is vocabulary. Here is what we mean by each term, and where a supplier might mean something else.
| Term | What we mean | Where it can differ |
|---|---|---|
| Span | Width of one bay between gutter lines | Sometimes used for total house width |
| Bay | Distance between arches along the house | Sometimes used for span |
| Eaves / gutter height | Height of gutter above ground | Sometimes measured to the arch spring line |
| Ridge height | Highest point of the roof | Measured to cover or to steel |
| Arch | The bent member forming the roof | Called a bow in a tunnel |
| Purlin | Member carrying the cover between arches | Called a rail in some markets |
| Gutter | Channel collecting water and tying bays | Called a gutter beam or gronda trave |
| Oval / HSO | Flattened tube used for arches | Proprietary profiles differ |
| Z275 | Coil coating, 275 g/m² both surfaces | Quoted as if it applied to fabricated parts |
| Hot-dip | Coating applied after fabrication | Thickness class varies by standard |
| MOQ | Minimum order quantity | Per item, per container, or per heat |
| FOB | Free on board at named port | Sometimes confused with delivered |
| Bundle | Strapped group of members | May be counted as a package in freight |
| Knocked down | Supplied unassembled | Not the same as un-fabricated |
When a quotation uses a term, ask which meaning. It is cheaper than a re-order.
Why this page exists
Most disputes we see are vocabulary, not quality. Two parties agreed on the word and disagreed on the thing.
NEXT
Read next
Pages that answer the question this page raises.
- 08Technical libraryTechnical guides for greenhouse frame specification: span and bay, snow and wind load, gal→
- 08.01Specify a frameHow to specify a greenhouse frame: span, bay, eaves, load case, covering, coating, fitting→
- RFQ builderBuild a greenhouse frame RFQ: select tube, profiles, gutters and system lines, add project→
NEXT STEP
Turn this into a quoted frame list
If this page answered the technical question, the next step is a number. Send the parameters and we will price the tube, profiles, gutters and fittings as one package.