Steam coils are circuited like standard water coils, designed for applications were the entering air temperature is 55 degrees or higher and are not suited for outside entering air. Steam distribution coils are manufactured for low temperature applications with a tube within tube design. Steam entering the header is distributed to the inner tubes. From the inner tubes the steam is then distributed through small holes or “Steam Jets”. These Steam Jets are directionally pierced, so that the steam helps push the condensate in the outer tube toward the outlet connection. The main decision in deciding what coil to use is your entering air temperature.
There are standard charts for steam pressure to tube wall thickness conversions. Below is a simple chart:
3 PSIG - 25 PSIG = 0.25" Copper Tube Wall
26 PSIG - 75 PSIG = 0.35" Copper Tube Wall
76 PSIG - 125 PSIG = 0.049" Copper Tube Wall or 0.035 " Carbon Steel Coil
125 PSIG and above = 0.035" Carbon Steel Tube Wall and 0.35 Stainless Steel Tube Wall (consult factory)
Steam distribution coils offer better distribution of the steam throughout the entire coil allowing steam condensate to exit as quickly as possible, allowing for an efficient effective steam coil. Standard steam coils reduce even distribution of steam and do not allow the condensate to exit the coil at a fast rate allowing for possible steam obstruction. Many times steam distribution coils are the primary product for steam heat.
All steam coil production is 15 business days on a standard cycle. Nationwide Coils, Inc offers expedited options of 3, 5, and 10 days for all emergency situations.
All steam distribution coils need to be pitched at minimum an 1/8" per foot to allow proper removal of condensate. Nationwide Coils provides to types of casings standard casing options and pitched in casing. The pitched in casing option is manufactured to be pitched within a level casing allowing the customer to install a level steam coil that is built with proper pitch. This along with placing your return connection at the lowest possible point on the header ensure proper and efficient operation of your steam coil. Standard Steam Coils do not need to be pitched for correct operation.