Welcome to the forum Mike,
You bring up a good point about what is considered a high pressure water rocket and present us with an opportunity to create a set of definitions. I think that people tend to over exaggerate the capabilities of their rockets in their youtube descriptions in an attempt to "get more views". While a standard set of definitions (once most people start using these) won't prevent some joker from calling their rocket "high pressure", it will expose their intentions to over exaggerate their rockets capabilities.
The classifications will be defined as follows:
1.
Normal water rocket: Any water rocket regardless of construction material launched at a pressure of less than 250PSI
250PSI can be reached using inexpensive compressors and hand pumps.
Materials for reinforcement to achieve the upper limit are relatively inexpensive such as winding with tape, fishing line, fiberglass, tape, and layering the bottles.
2.
Moderate pressure water rocket: (suggestions for a better name anyone?) Any water rocket regardless of construction material launched at a pressure of 250PSI to 500PSI
These pressures can be achieved using moderately expensive compressors or bottled air.
Rockets will certainly need reinforcements to achieve this pressure range and the materials are moderately expensive such as Kevlar.
3.
High pressure water rocket: Any water rocket regardless of construction material launched at a pressure higher than 500PSI
These pressures are achieved using expensive compressors or bottled air
Rockets will certainly need reinforcements to achieve this pressure range and the materials are expensive such as Carbon Fiber.
Thank you for bringing this up as it may have implications as far as safety rules, minimum stand off distances,etc.
There are not really any age limits but it would be recommended that persons under 16 stick to standard rockets unless assisted by an adult.
